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Mathematics 19 Online
OpenStudy (carolina4567):

Use the image below to answer the following question. Find the value of sin x° and cos y°. What relationship do the ratios of sin x° and cos y° share?

OpenStudy (carolina4567):

OpenStudy (carolina4567):

Help Me Please Im Really Behind

OpenStudy (carolina4567):

@ganeshie8 @amistre64 @mathmale

OpenStudy (carolina4567):

I only have this and another question left

OpenStudy (muzzack):

woow, i dont know this yet sorry :)

OpenStudy (carolina4567):

Im in 10th grade

OpenStudy (mathmale):

First, some basics: Knowing the definitions of the sine and cosine function is essential. What are these definitions? For example: \[\tan x = \frac{ opposite~side }{ adjacent~side }\]

OpenStudy (mathmale):

Write out similar definitions for the sine and cosine of the angle x.

OpenStudy (carolina4567):

Sine is opposite/ hypotenuse and cosine adjacent/ hypotenuse and if they equal 90 they must be complemantary angles

OpenStudy (mathmale):

Next: Note that x and y are "complementary angles." What does that mean to you?

OpenStudy (carolina4567):

That they equal to 90 degrees

OpenStudy (mathmale):

Nice work; just a little tweak to the wording: If the SUM of x and y is 90 degrees, then x and y are complementary angles. (You must mention the word "sum.")

OpenStudy (carolina4567):

Ok

OpenStudy (mathmale):

Now look at angle x. Which side of this triangle is "opposite" angle x? Which side is the hypotenuse? Knowing these two values, find the ratio opp side sin x = -------------- hyp

OpenStudy (mathmale):

which must be a fraction between 0 and 1.

OpenStudy (carolina4567):

Sin x = 3/4

OpenStudy (carolina4567):

is that it?

OpenStudy (mathmale):

No, unfortunately. Your 3/4 is the TANGENT of the angle x. You correctly defined the SINE of angle x. Find sin x using the appropriate side lengths given in the figure.

OpenStudy (mathmale):

If the 2 "legs" of this triangle are 3 and 4 respectively, what is the length of the hypotenuse? Hint: use the Pythagorean Theorem to find the length of the hyp.

OpenStudy (carolina4567):

Umm lets see

OpenStudy (mathmale):

Those trig functions and the Pyth Theorem are extremely important and are worth memorizing and practicing.

OpenStudy (carolina4567):

a*2 + B*2 = C*2 3*2 + 4*2 = C*2 9 + 16 = C*2 25 = c*2 c = 5

OpenStudy (carolina4567):

is this correct

OpenStudy (mathmale):

yes, the length of the hyp is 5. So the sine of x is what fraction?

OpenStudy (carolina4567):

Sin x = 3/5

OpenStudy (mathmale):

Great. Got it. For review: What is the definition of the cosine function?

OpenStudy (mathmale):

What is cos x? What is cos y?

OpenStudy (carolina4567):

cosine is adjacent/hypotenuse

OpenStudy (carolina4567):

4/5

OpenStudy (carolina4567):

cos x = 4/5

OpenStudy (mathmale):

Great. That's the definition. Now, what is cos x? Right you are. Now, what is cos y?

OpenStudy (carolina4567):

cos y ? umm im a little confused what is cos y?

OpenStudy (mathmale):

The principle is exactly the same. Find angle y. Identify its adjacent side and its hypotenuse. Write the cosine of y exactly as you did before: cos y = adj / hyp

OpenStudy (carolina4567):

So it would be cos x = 4/5

OpenStudy (carolina4567):

So this would mean that my answer is sin x = 3/5 and cos y = 4/5 correct

OpenStudy (carolina4567):

And that there relationship would be that there sum is to 92 degrees meaning that there complemantary correct?

OpenStudy (carolina4567):

90 degrees my bad

OpenStudy (carolina4567):

@mathmale

OpenStudy (carolina4567):

@amistre64 can you help me finish up

OpenStudy (carolina4567):

@ganeshie8

OpenStudy (carolina4567):

Anyone

OpenStudy (carolina4567):

@phi

OpenStudy (carolina4567):

@phi mathmale is offline I just need to know if its correct

OpenStudy (phi):

where are you in the question ?

OpenStudy (phi):

. Find the value of sin x° and cos y° you should get the same ratio for these.

OpenStudy (carolina4567):

Sorry umm we are done with the question I just need to know if its correct

OpenStudy (phi):

to do this use the definitions (people use SOH CAH TOA to remember them) sin use SOH: sin= opp/hyp sin x means put your finger on the x angle. go "across" to the other (i.e. opposite ) side and read off 3 as you know , they hypotenuse is 5, you get sin x = 3/5 I

OpenStudy (carolina4567):

Yes and cos is cos x = 4/5

OpenStudy (carolina4567):

There complemantary which means that they sum up to 90 degrees thats there relationship that they share together.

OpenStudy (phi):

now do cos y° cos: CAH cos= adjacent/hyp put you finger on angle y. Find the adjacent side . It is the side that makes up part of the angle but is NOT the hypotenuse. You should find 3 cos y = 3/5

OpenStudy (carolina4567):

I got it now. Can you help me with one last question please.

OpenStudy (carolina4567):

An observer (O) is located 660 feet from a tree (T). The observer notices a hawk (H) flying at a 35° angle of elevation from his line of sight. How high is the hawk flying over the tree? You must show all work and calculations to receive full credit.

OpenStudy (phi):

you found cos x , but they want cos y

OpenStudy (carolina4567):

OpenStudy (phi):

if you are doing a different question, pleasemake a new post.

OpenStudy (carolina4567):

arent cos x and y the same thing

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