Answer:
The aprox, numbers:
4.1633 and 8.3266
Step-by-step explanation:
a = 2b
a² - b² = 52
then:
(2b)² - b² = 52
4b² - b² = 52
3b² = 52
b² = 52/3
b² = 17.333
√b² = √17.333
b = 4.1633 aprox.
a = 2b
a = 2*4.1633
a = 8.3266
Check:
8.3266² - 4.1633² = 52
69.333 - 17.333 = 52
Determine whether the following statement is true or false. If it is false, rewrite it as a true statement. A double-blind experiment is used to increase the placebo effect. Choose the correct answer below. A. The statement is false. Double blinding has no effect on the placebo effect. B. The statement is false. Double blinding is used to increase the randomization. C. The statement is true. D. The statement is false. Double blinding is used to decrease the placebo effect.
Answer:
D. The statement is false. Double blinding is used to decrease the placebo effect.
Step-by-step explanation:
In a double blind study, neither researchers nor the participants know which group is receiving the placebo. If the researchers do not know which group took the medication, they cannot influence the behavior of this group, knowingly or nor, by suggesting how they should behave.
Therefore, a double-blind experiment is used to decrease the placebo effect.
What is the focus of the parabola? y=−1/4x2−x+3
Answer: Focus = (-2, 3)
Step-by-step explanation:
[tex]y=-\dfrac{1}{4}x^2-x+3\\\\\rightarrow a=-\dfrac{1}{4},\ b=-1[/tex]
First let's find the vertex. We do that by finding the Axis-Of-Symmetry:
[tex]AOS: x=\dfrac{-b}{2a}\quad =\dfrac{-(-1)}{2(\frac{-1}{4})}=\dfrac{1}{-\frac{1}{2}}=-2[/tex]
Then finding the maximum by inputting x = -2 into the given equation:
[tex]y=-\dfrac{1}{4}(-2)^2-(-2)+3\\\\y=-1+2+3\\\\y=4[/tex]
The vertex is: (-2, 4)
Now let's find p, which is the distance from the vertex to the focus:
[tex]a=\dfrac{1}{4p}\\\\\\-\dfrac{1}{4}=\dfrac{1}{4p}\\\\\\p=-1[/tex]
The vertex is (-2, 4) and p = -1
The focus is (-2, 4 + p) = (-2, 4 - 1) = (-2, 3)
A researcher is interested in determining the mean energy consumption of a new
compact florescent light bulb. She takes a random sample of 41 bulbs and determines
that the mean consumption is 1.3 watts per hour with a standard deviation of 0.7.
When constructing a 97% confidence interval, which would be the most appropriate
value of the critical value?
A) 1.936
B) 2.072
C) 2.250
D) 2.704
E) 2.807
Answer:
The most appropriate value of the critical value is 2.289.
Step-by-step explanation:
We are given that a researcher takes a random sample of 41 bulbs and determines that the mean consumption is 1.3 watts per hour with a standard deviation of 0.7.
We have to find that when constructing a 97% confidence interval, which would be the most appropriate value of the critical value.
Firstly, as we know that the test statistics that would be used here is t-test statistics because we don't know about the population standard deviation.
So, for finding the critical value we will look for t table at (41 - 1 = 40) degrees of freedom at the level of significance will be [tex]\frac{1 - 0.97}{2} = 0.015[/tex] .
Now, as we can see that in the t table the critical values for P = 1.5% are not given, so we will interpolate between P = 2.5% and P = 1%, i.e;
[tex]\frac{0.015 - 0.025}{0.025-0.01}= \frac{\text{Critcal value}-2.021}{2.021-2.423}[/tex]
So, the critical value at a 1.5% significance level is 2.289.
Which of the following functions best describes this graph ?
Answer:
answer D
Step-by-step explanation:
Lets have a look to the graph and to the each of given functions.
As we can see in graph it intersects X in points (-3;0) and (-6;0) that means the function has the roots x1=-3 and x2=-6
Function A has the roots x1=+3 and x2=+6 => doesn' t fit
Function B has only 1 root x=2 , so can be factorized y=(x-2)^2 => doesn' t fit
Function C has 2 roots x1=4 and x2=-5 => doesn' t fit
Function D can be factotized as y=(x+6)*(x+3) so has 2 roots x1=-6 x2=-3 => exactly what we need!!!
We can also notice that the coefficient near x² is equal to 1 and is positive.
That means the legs of the graph directed up,- this is exactly like in our graph. It gives us extra argument why we choose D.
Assume that IQ scores are normally distributed, with a standard deviation of 16 points and a mean of 100 points. If 60 people are chosen at random, what is the probability that the sample mean of IQ scores will not differ from the population mean by more than 2 points
Answer:
The probability that the sample mean of IQ scores will not differ from the population mean by more than 2 points is 0.67
Step-by-step explanation:
Please check attachment for complete solution and step by step explanation
Scores made on a certain aptitude test by nursing students are approximately normally distributed with a mean of 500 and a variance of 10,000. If a person is about to take the test what is the probability that he or she will make a score of 650 or more?
Answer:
0.0668 or 6.68%
Step-by-step explanation:
Variance (V) = 10,000
Standard deviation (σ) = √V= 100
Mean score (μ) = 500
The z-score for any test score X is:
[tex]z=\frac{X-\mu}{\sigma}[/tex]
For X = 650:
[tex]z=\frac{650-500}{100}\\z=1.5[/tex]
A z-score of 1.5 is equivalent to the 93.32nd percentile of a normal distribution. Therefore, the probability that he or she will make a score of 650 or more is:
[tex]P(X\geq 650)=1-P(X\leq 650)\\P(X\geq 650)=1-0.9332\\P(X\geq 650)=0.0668=6.68\%[/tex]
The probability is 0.0668 or 6.68%
The probability that he or she will make a score of 650 or more is 0.0668.
Let X = Scores made on a certain aptitude test by nursing students
X follows normal distribution with mean = 500 and variance of 10,000.
So, standard deviation = [tex]\sqrt{10000}=100[/tex].
z score of 650 is = [tex]\frac{\left(650-500\right)}{100}=1.5[/tex].
The probability that he or she will make a score of 650 or more is:
[tex]P(X\geq 650)\\=P(z\geq 1.5)\\=1-P(z<1.5)\\=1-0.9332\\=0.0668[/tex]
Learn more: https://brainly.com/question/14109853
The population density, D, in people/square mile (p/mi²), for the large city Westport is related to the distance x (in miles) from the city’s center by the equation:________.
D=4300x /x^2 + 40.
a. Describe what happens to West-port's population density as the distance from the city’s center changes from one mile to six miles. What may explain this phenomenon?
b. Describe what happens to West-port's population density as the distance from the city’s center changes from ten miles to thirty miles.
c. Describe the end-behavior of this function? What may explain this phenomenon?
d. In what areas of the city is the population density below 200 p/mi²?
Answer:
Step-by-step explanation:
D=4300x /x² + 40.
x = 1
D = 4300 / 41 = 104.88 p / mi²
x = 6
D = 25800 / 76
= 339.47 p / mi²
Population density increases as we go away from city's centre .
b )
x = 10
D=4300x /x² + 40.
D = 307.14 p/ mi²
x = 30
D = 137.23 p / mi²
Population decreases .
c )
when x is very high , density will decrease due to squared denominator whose value increases very fast .
d )
D < 200
4300x /x² + 40 < 200
4300 x < 200 x² + 8000
43 x < 2 x² + 80
2 x² - 43 x + 80 > 0
( x - 19.44 ) ( x - 2.05 ) > 0
Range x < 2.05
x > 19.44
What is the slope of the line described by the equation y-1=3x
Answer:
Hey there!
The line can be expressed into y intercept form, y=3x+1.
Thus, in y=mx+b form, m is the slope, and we see that 3 is the slope of the line.
Let me know if this helps :)
A square mesaures 80 yd on a side. Bob and Rob begin running from the same corner. Bob runs along a side to an adjacent corner, and Rob runs along a diagonal to an opposite corner. They arrive at their respective corners at the same time. If Bob's speed was 8mi/h, what was Rob's speed? Express your answer as a decimal to the nearest tenth.
Answer:
c = 11.3 mi/h
Step-by-step explanation:
Since Square has all of the same sides, hence bobs speed will be the same for all of the sides.
All of the sides are equal in a square
=> Let's consider the two sides along with the diagonal a right angled triangle
=> [tex]c^2 = a^2 + b^2[/tex]
Where c is the speed of Rob along the diagonal and b and c is the speed of Bob along the side
=> [tex]c^2 = 8^2+8^2[/tex]
=> [tex]c^2 = 64+64[/tex]
=> [tex]c^2 = 128\\[/tex]
Taking sq root on both sides
=> c = 11.3 mi/h
Students in management science class have just received their grades on the first test. The instructor has provided information about the first test grades in some previous classes as well as the final average for the same students. Some of these grades have been sampled and are as follow:
1st test Grade 98 77 88 80 96 61 64 95 79
Final average 93 78 84 75 84 64 66 95 86
Develop a regression model that could be used to predict the final average in the course based on the first test grade.
Predict the final average of a students who made an 83 on the first test.
Give the value of r and r2 for this model.
Interpret the value of r2 in the context of this problem.
Answer:
The regression model is:
y = 20.29 + 0.73·x
Step-by-step explanation:
In this case a regression model is to be formed to predict the final average in the course based on the first test grade.
Use Excel to form the regression model.
The output is attached below.
The regression model is:
y = 20.29 + 0.73·x
Predict the final average of a students who made an 83 on the first test as follows:
y = 20.29 + 0.73·x
= 20.29 + 0.73 × 83
= 80.88
The final average of a students who made an 83 on the first test would be 80.88.
From the output:
R² = 0.839
Then the correlation coefficient will be:
[tex]r=\sqrt{R^{2}}=\sqrt{0.839}=0.91597\approx 0.92[/tex]
The value of r is 0.92.
The coefficient of determination R² specifies the percentage of the variance in the dependent-variable (Y) that is forecasted or explained by linear regression and the forecaster variable (X, also recognized as the independent-variable).
In this case, the R² value of 0.839 implies that 83.9% of the variation in the final average can be explained by the grades in the first test.
F(x)=8*(1/2)^x table
Answer:
Show the table or make ur question a little more clear so I can help
Step-by-step explanation:
A restaurant operator in Accra has found out that during the partial lockdown, if she sells a plate of her food for GH¢20 each, she can sell 300 plates, but for each GH¢5 she raises the price, 10 less plates are sold.
Draw a table of cost relating to number of plates using 6 values of cost and its corresponding number of plates bought.
What price in GH¢ should she sell the plates to maximize her revenue?
Answer:
Step-by-step explanation:
First, note this parameters from the question.
We let x = number of $5 increases and number of 10 decreases in plates sold.
Our Revenue equation is:
R(x) = (300-10x)(10+5x)
We expand the above equation into a quadratic equation by multiplying each bracket:
R(x) = 3000 + 1500x - 3000x - 1500x^2
R(x) = -1500x^2 - 1500x + 3000 (collect like terms)
Next we simplify, by dividing through by -1500
= 1500x^2/1500 - 1500x/1500 + 3000/1500
= X^2 - x + 2
X^2 - x + 2 = 0
Next, we find the axis of symmetry using the formula x = -b/(2*a) where b = 1, a = 1
X = - (-1)/2*1
X = 1/2
Number of $5 increases = $5x1/2 = $2.5
=$2.5 + $20 = $22.5 ticket price gives max revenue.
Which of the following is an exterior angle of triangle BHE? Yes or no
Answer:
Im not 100% sure, but I think it is:
No
No
No
Yes
67.805 what is the value of the 0 help please asap!
Answer:
hundreths
Step-by-step explanation:
After the decimal there is tenths, hundreths thousandnths, tens of thousands e.t.c
Answer:
Hello! The answer will be hundredths.
Step-by-step explanation:
The 5 means the thousandths.
The 0 means the hundredths.
The 8 means the tenths.
The 7 means the ones
And the 6 means the tens.
Hope this helps! :)
( below I attached a picture, which might be helpful.)
7x-x combine the like terms to create an equivelent expression
Answer:
6x
Step-by-step explanation:
7x - x
Factor out x
x( 7-1)
6x
Answer:
6x
Step-by-step explanation:
7x - x
Apply rule : a = 1a
x = 1x
7x - 1x
Factor out x.
(7 - 1)x
(6)x
boxes of raisins are labled as containing 22 ounces. Following are the weights, in the ounces, of a sample of 12 boxes. It is reasonable to assume that the population is approximatly normal.
21.88 21.76 22.14 21.63 21.81 22.12 21.97 21.57 21.75 21.96 22.20 21.80
Required:
Construct a 99% confidence interval for the mean weight.
Answer:
The 99 % confidence interval on the basis of mean is ( 21.7393 ; 22.0257)
Step-by-step explanation:
Mean = Sum of observations / Number of observations
Mean = 21.88 +21.76 +22.14 +21.63+ 21.81 +22.12+ 21.97+ 21.57+ 21.75+ 21.96 +22.20 +21.80/ 12
Mean =x`= 262.59/12= 21.8825
Standard Deviation = s= ∑x²/n - ( ∑x/n)²
∑x²/n= 478.7344 +473.4976 + 490.1796+467.8569+ 475.6761 + 489.2944+ 482.6809+ 465.2649+ 473.0625+ 482.2416 +492.84 + 475.24/ 12
∑x²/n= 5746.5689/12= 478.8807 = 478.881
Standard Deviation = s= ∑x²/n - ( ∑x/n)²
s= 478.881- (21.8825)²= 478.881-478.843= 0.037
The confidence limit 99% for the mean will be determined by
x` ± α(100-1) √s/n
Putting the values in the above equation
= 21.8825 ± 2.58 √0.037/12
Solving the square root
= 21.8825 ± 2.58 (0.05549)
Multiplying the square root with 2.58
=21.8825 ± 0.1432
Adding and subtracting would give
21.7393 ; 22.0257,
Hence the 99 % confidence interval on the basis of mean is ( 21.7393 ; 22.0257)
The five numbers summary for a data set is shown below. What is the range of the data set? 3, 7, 11, 14, 16
Answer:
13
Step-by-step explanation:
The range of a set of data is the difference between the highest and lowest values in the set.
So, in order to find the range, you first order the data from least to greatest. Which it is already.
3, 7, 11, 14, 16
Then subtract the smallest value from the largest value in the set.
16 - 3 = 13
Hope this helps you out! : )
Letters a, b, c, and d are angles measures. Lines m and n are cut by transversal p. At the intersection of lines p and m, labeled clockwise, from uppercase left, the angles are: a, b, c, blank. At the intersection of lines p and n, labeled clockwise, from uppercase left, the angles are: blank, blank, d, blank. Which equation is enough information to prove that lines m and n are parallel lines cut by transversal p? Select three options. a = c a = d c = d b + c = 180° b + d = 180°
Answer:
b, c, e
Step-by-step explanation:
the reasons have to include an angle from both of the parallel lines. by using process of elimination it is b, c, e. I also got it right
Answer:
B. a=d
C. c=d
E. b + d=180°
Step-by-step explanation:
Got Correct On MyPath.
The coldest temperature ever recorded in New York City was -15F on Feb 9, 1934. The next day, the temperature rose
Write an expression for the temperature on Feb 10
Answer:
x = -15 + y
Step-by-step explanation:
Let next days temperature be x and the temperature rise be y
=> x = -15 + y
The next day's temperature will be more since it "rose".
Answer:
[tex]\boxed{x=-15+y}[/tex]
Step-by-step explanation:
Let the temperature on Feb 10, 1934 be x.
Let the temperature increase be y.
On Feb 9, the temperature was -15F.
On Feb 10, the temperature increased.
[tex]x=-15+y[/tex]
please help ASAP!!!!!!!!!
Answer:
sec B = 17 / 15
Step-by-step explanation:
Sec theta = hyp / adj
sec B = 17 / 15
Answer:
17/15
Step-by-step explanation:
The secant of an angle is the ratio of the hypotenuse to the adjacent angle (it is also the reciprocal of cosine).
secθ=hypotenuse/adjacent
sec(∠B)= hypotenuse/adjacent
The hypotenuse in this triangle is 17, because it is opposite the right angle or the little square.
sec(∠B)=17/adjacent
The side adjacent, or next to angle B is 15.
sec(∠B)= 17/15
This fraction cannot be reduced further, therefore the secant of angle B is 17/15.
Suppose taxi fares from Logan Airport to downtown Boston is known to be normally distributed and a sample of seven taxi fares produces a mean fare of $21.51 and a 95% confidence interval of [$20.52, $22.48]. Which of the following statements is a valid interpretation of the confidence interval?
a. 95% of all taxi fares are between $20.52 and $22.48.
b. We are 95% confident that a randomly selected taxi fare will be between $20.52 and $22.48.
c. We can report that the average taxi fare between Logan Airport and downtown Boston will fall between $20.52 and $22.48.
d. With 95% confidence
Answer:
The correct option is C
Step-by-step explanation:
From the question we are told that
The sample mean is [tex]\= x =[/tex]$21.51
The 95% confidence level interval is [$ 20.52 , $22.48]
Generally the 95% confidence level interval is mathematically represented as
[tex]\= x - MOE < \mu < \= x + MOE[/tex]
Where MOE is the margin of error which defines in percentage the amount by which the sample mean taxi fare(for the 7 taxi ) will differ from the average taxi fare between Logan Airport and downtown Boston will fall between
Also [tex]\mu[/tex] is the average taxi fare between Logan Airport and downtown Boston
So we see that the this 95% confidence level interval tells us that the average taxi fare between Logan Airport and downtown Boston will fall between $20.52 and $22.48.
Find the amount of money in savings account if $3200 was deposited for 3 years at 40% interest compounded annually. Find the interest
Step-by-step explanation:
Formula for compound interest is given by
[tex]A = P(1 + R) ^{n} [/tex]
Where
A is the amount at the end of the period
P is the principal
R is the rate
n is the period
The interest = A - P
From the question
P = $ 3200
n = 3 years
R = 40%
So we have
[tex]A = 3200 \times 2.744[/tex]
A = $ 8780.80
The amount is $ 8780.80The interest is
$ 8780.80 - $3200
= $ 5580.80Hope this helps you
2 (3z-4) <16 Which one of the following values of z is a solution for the inequality
Answer:
z < 4
Step-by-step explanation:
2(3z-4) < 16
Divide by 2 on both sides
3z-4 < 8
Add 4 to both sides
3z < 12
Divide by 3 on both sides
z < 4
A manufacturer claims that the mean tensile strength of thread A exceeds the average tensile strength of thread B. To test his claim, 16 sample pieces of each type of thread are tested under similar conditions. Type A thread had a sample average tensile strength of 185 kg with a standard deviation of 6 kg, while type B thread had a sample average tensile strength of 178 kg with a standard of 9 kg. Assume that both populations are normally distributed and the variances are equal. Test the manufacturers claim using a = 0.05 level of significance.
The complete part of the first sentence is;
A manufacturer claims that the average tensile strength of thread A exceeds the average tensile strength of thread B by at least 12 kilograms.
Answer:
we fail to reject the null hypothesis and conclude that the difference of the average tensile strength of thread A and thread B is less than 12
Step-by-step explanation:
We are given;
n_A = 16
n_B = 16
x'_A = 185 kg
x'_B = 178 kg
s_A = 6 kg
s_B = 9 kg
Let μ_A denote the population average tensile strength of thread A
Also, Let μ_B represent the population average tensile strength of thread B
Thus;
Null Hypothesis; H0;μ_A - μ_B ≤ 12
Alternative hypothesis;H1; μ_A - μ_B > 12
From the image attached, with a significance level of 0.05, the critical value for right tailed is 1.645. So we will reject the hypothesis is z > 1.645
Formula for z is;
z = (x'_A - x'_B - d_o)/√((s_A²/n_A) + (s_B²/n_B))
Plugging in the relevant values, we have;
z = (185 - 178 - 12)/√((6²/16) + (9²/16))
z = -5/2.7041634566
z = - 1.849
Since the z-value is less than 1.645,we fail to reject the null hypothesis and conclude that the difference of the average tensile strength of thread A and thread B is less than 12
Jose added up his work hours for his paycheck. Last week he worked hours 25 5/8. This week he worked hours 32 5/6. How many total hours did he work in two weeks? with steps
Answer:
58 hours
Step-by-step explanation:
First week: 25 5/8 hours = 25 hrs 37 mins and 30 sec
Second weeK: 32 5/6 hrs = 32 hrs and 50 mins
To find the toal time in minutes
(37 + 50) mins = 1 hr 27 mins
Threfore, total number of hours he worked in two weeks:
(25 + 32 + 1) hrs = 58 hours
Can two events with nonzero probabilities be both independent and mutually exclusive? Choose the correct answer below. A. Yes, two events with nonzero probabilities can be both independent and mutually exclusive when their probabilities add up to one. B. No, two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually exclusive, then when one of them occurs, the probability of the other must be zero. C. Yes, two events with nonzero probabilities can be both independent and mutually exclusive when their probabilities are equal. D. No, two events with nonzero probabilities cannot be independent and mutually exclusive because independence is the complement of being mutually exclusive.
Answer:
Step-by-step explanation:
B. No, two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually exclusive, then when one of them occurs, the probability of the other must be zero.
For two mutually exclusive events , with non- zero probabilities , when one occurs , the other can not happen . In this way they become dependent events . In this way , for two events to be both independent and mutually exclusive , at least one of the two events must have zero probability .
It should be noted that two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually exclusive, then when one of them occurs, the probability of the other must be zero.
Mutually exclusive events simply means the events that cannot take place at the same time. The occurrence of one of the events will prevent the other event from occuring.
Therefore, two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually exclusive, then when one of them occurs, the probability of the other must be zero.
Read related link on:
https://brainly.com/question/15179003
A college administrator predicts that the proportion of students that are nursing majors is greater than 40%. To test this, a group of 400 students are randomly selected and it's determined that 190 are nursing majors. The following is the setup for this hypothesis test:
H0:p=0.40
Ha:p>0.40
In this example, the p-value was determined to be 0.001. Find the conclusion and interpret the results for this hypothesis test for a proportion (use a significance level of 5%)
Answer:
Step-by-step explanation:
Using the following data:
H0:p=0.40 (null hypothesis)
Ha:p>0.40 (alternative hypothesis)
The p-value was determined to be 0.001.
a significance level of 5%
Since the p value (0.001) is less than the significance level (0.05), we will reject the null hypothesis and then we would conclude that the proportion of students that are nursing majors is greater than 0.4.
Answer:
p value= 0.131
Step-by-step explanation:
Since we have calculated the test statistic, we can now proceed to find the p-value for this hypothesis test.Using the test statistic and since the hypothesis test is a left tailed test, the p-value will then be the area under the standard normal curve to the left of the test statistic of -1.12.Using the Standard Normal table given above, the area under the standard normal curve to the left of the test statistic of -1.12 is 0.131 (rounded to 3 decimal places.Thus the p-value = 0.131.
Question 20 of 21
In the triangle shown below, what is the approximate value of X?
12
O A. 20.78 units
O B. 26.83 units
O c. 12 units
D. 18 units
Answer:
O A. 20.78 units
Step-by-step explanation:
APEXX
In the following problem, the expression is the right side of the formula for cos (alpha - beta) with particular values for alpha and beta. cos (79 degree) cos (19 degree) + sin (79 degree) sin (19 degree)
Identify alpha and beta in each expression.
The value for alpha: degree
The value for beta: degree
Write the expression as the cosine of an angle. cos degree
Find the exact value of the expression. (Type an exact answer, using fraction, radicals and a rationalized denominator.)
Answer:
1. [tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex]
2. [tex]cos(60)[/tex]
3. [tex]cos(60) = \frac{1}{2}[/tex]
Step-by-step explanation:
Given
[tex]cos(\alpha - \beta )[/tex]
[tex]cos(79)cos(19) + sin(79)sin(19)[/tex]
Solving for [tex]\alpha[/tex] and [tex]\beta[/tex]
In trigonometry;
[tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex]
Equate the above expression to [tex]cos(79)cos(19) + sin(79)sin(19)[/tex]
[tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex] and [tex]cos(\alpha - \beta ) = cos(79)cos(19) + sin(79)sin(19)[/tex]
By comparison
[tex]cos\alpha\ cos\beta + sin\alpha\ sin\beta = cos(79)cos(19) + sin(79)sin(19)[/tex]
Compare expression on the right hand side to the left hand side
[tex]cos\alpha\ cos\beta = cos(79)cos(19) \\\\ sin\alpha\ sin\beta = sin(79)sin(19)[/tex]
This implies that
[tex]cos\alpha\ = cos(79)\\cos\beta = cos(19) \\\\ and\\\\sin\alpha\ = sin(79)\\sin\beta = sin(19)[/tex]
By further comparison
[tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex]
Substitute [tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex] in [tex]cos(\alpha - \beta )[/tex]
[tex]cos(\alpha - \beta ) = cos(79 - 19)[/tex]
[tex]cos(\alpha - \beta ) = cos(60)[/tex]
Hence, the expression is [tex]cos(60)[/tex]
Solving for the exact values;
Express [tex]cos(60)[/tex] as a difference of angles
[tex]cos(60) = cos(90 - 30)[/tex]
Recall that [tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex]
So;
[tex]cos(90- 30 ) = cos(90) cos(30) + sin(90) sin(30)[/tex]
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In trigonometry;
[tex]cos(90) = 0[/tex]; [tex]cos(30) = \frac{\sqrt{3}}{{2}}[/tex]; [tex]sin(90) = 1[/tex]; [tex]sin(30) = \frac{1}{2}[/tex];
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[tex]cos(90- 30 ) = cos(90) cos(30) + sin(90) sin(30)[/tex] becomes
[tex]cos(90- 30 ) = 0 * \frac{\sqrt{3}}{2} + 1 * \frac{1}{2}[/tex]
[tex]cos(90- 30 ) = 0 + \frac{1}{2}[/tex]
[tex]cos(90- 30 ) = \frac{1}{2}[/tex]
Hence;
[tex]cos(60) = \frac{1}{2}[/tex]
The marginal cost (dollars) of printing a poster when x posters have been printed is given by the following equation. C'(x)=x^-3/4 Find the cost of printing 142 more posters when 18 have already been printed.
The cost of printing 142 more posters when 18 have already been printed is $________.
(Round to the nearest cent as needed.)
Answer:
The cost of printing 142 more posters when 18 has already been printed is $5.57.
Step-by-step explanation:
We are given that the marginal cost (dollars) of printing a poster when x posters have been printed is given by the following equation C'(x)=x^-3/4.
The given equation is: [tex]C'(x) = x^{\frac{-3}{4} }[/tex]
The cost of printing 142 more posters when 18 have already been printed is given by;
Integrating both sides of the equation and using the limits we get;
[tex]\int_{a}^{b} C'(x) dx=\int_{18}^{142} x^{\frac{-3}{4}}dx[/tex]
As we know that [tex]\int\limits {x}^{n} \, dx = \frac{x^{n+1} }{n+1}[/tex] , so;
= [tex]\frac{x^{\frac{-3}{4}+1 } }{\frac{-3}{4}+1 } ]^{142} __1_8[/tex]
= [tex]\frac{x^{\frac{1}{4} } }{\frac{1}{4} } ]^{142} __1_8[/tex]
= [tex]4[x^{\frac{1}{4} } } ]^{142} __1_8[/tex]
= [tex]4[(142)^{\frac{1}{4} }- (18)^{\frac{1}{4} }} ][/tex]
= $5.57
Hence, the cost of printing 142 more posters when 18 has already been printed is $5.57.