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Naya [18.7K]
3 years ago
13

Law of cosines: a2 = b2 + c2 – 2bccos(A)

Mathematics
2 answers:
andrezito [222]3 years ago
8 0

The correct answer is:

D. y^{2}=9^{2}+19^{2}-2(9)(19)cos(41)

|Huntrw6|

damaskus [11]3 years ago
3 0
In this case,
a = y
b = 9
c = 19
So...
a^2 = b^2 + c^2 - 2bc*\cos(A)
y^2 = 9^2 + 19^2 - 2*9*19*\cos(41^{\circ})
which means the answer is choice D
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Triangle + triangle + square = 23<br> Triangle x square = 60<br> Triangle?<br> Square?
Ira Lisetskai [31]
2 triangle+square=23
square=60/triangle

2 triangle+60/triangle=23

2 triangle^2+60=23 triangle

2 triangle^2-23 triangle+60=0

solving quadratic equation we get

triangle=15/2  , 4
15/2 is not possible so triangle=4
square=15
7 0
4 years ago
Read 2 more answers
Please explain how to do #6 i know the work is right but i don’t understand it
mariarad [96]
Since this is part of a packet, there's a lot of prior knowledge you need to understand the question.
1) The angle of elevation is the angle between the horizontal and the light of sight from the object to the observer (see picture 1).

2) A lot of the units are from work done by an Indian astronomer. The line of sight (light blue in picture 1) is r = 3438 (I think you might have forgotten to finish writing the number). r, or 3438, is the distance from the earth to the sun used by Indian Astronomers. 

3) The table shows units in jya(θ<span>°). Jya is a Sanskrit (ancient Indian language) word. It stands for the length of half of a chord that connects two endpoints of a circle (kinda confusing and more information than you need to know - but it's the green line in picture 2).
What's important is: </span>jya(θ°) = r*sin(θ°)



Now let's tackle the problem:
1) You know that the angle of elevation is 67.5°. Using the chart, the only important value is the second from the bottom. jya(67.5°) = 3177. 

2) Remember that jya(θ°) = r*sin(θ°). 
Also remember that sine of an angle is \frac{opposite}{hypotenuse}. In this problem, r, the distance from the earth to the sun, happens to be the hypotenuse of the triangle since its the longest edge. 

3) Notice that you're dividing jya(θ°) (aka r*sin(θ°)) by r = 3438. That will give you sin(θ°) by itself. Then you're multiplying that sin(θ°) by 1 AU, which we are told is the actual distance of the hypotenuse/distance from earth to sun. Since sine = \frac{opposite}{hypotenuse} that gives you the apparent length of the opposite side = apparent height of the sun.

The math is a bit weird, but you're basically multiplying sine by the apparent distance 1AU to get the apparent height, instead of multiplying sine by the estimated height r = 3438. Dividing 3177 by 3438 gives you sin(67.5°). Then multiplying sin(67.5°) by the apparent hypotenuse, 1AU, gives you the apparent height. That's how I'm understanding it!

6 0
3 years ago
A random sample of 1000 people was taken. Four hundred fifty of the people in the sample favored Candidate A. The 95% confidence
KatRina [158]

Answer:

The 95% confidence interval would be given (0.419;0.481).

Step-by-step explanation:

Data given and notation  

n=1000 represent the random sample taken    

X=450 represent the people in the sample favored Candidate A

\hat p=\frac{450}{1000}=0.45 estimated proportion of people in the sample favored Candidate A  

\alpha=0.05 represent the significance level

Confidence =0.95 or 95%

p= population proportion of people in the sample favored Candidate A

Solution to the problem

The confidence interval would be given by this formula

\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}

For the 95% confidence interval the value of \alpha=1-0.5=0.05 and \alpha/2=0.025, with that value we can find the quantile required for the interval in the normal standard distribution.

z_{\alpha/2}=1.96

And replacing into the confidence interval formula we got:

0.45 - 1.96 \sqrt{\frac{0.45(1-0.45)}{1000}}=0.419

0.45 + 1.96 \sqrt{\frac{0.45(1-0.45)}{1000}}=0.481

And the 95% confidence interval would be given (0.419;0.481).

We are confident (95%) that about 41.9% to 48.1% of the people are favored Candidate A.  

3 0
3 years ago
Find the indicated side of the triangle.<br> 10<br> b<br> 45°<br> a<br> b =
Korvikt [17]

Answer:

Step-by-step explanation:

a = b

Pythagorean Theorem:

b = 10/√2

6 0
3 years ago
30 points! Inflection points question. Okay, so I know that an inflection point is where the function is continuous and the conc
Pavel [41]
Find the concavity changes of f(x).
Give the x-coordinates.

So, the answer to the multiple choice question is -1 and 5 since those points are where f''(x) changes sign.

Note: You can tell that you're supposed to find the concavity changes of f(x) and not f''(x) because from the graph it's obvious that the concavity of f"(x) doesn't change.
5 0
4 years ago
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