Evaluate sin(Cos^-1 * (-15/17)) .

Question

anonymous · Answer

Ok ... what sides of a right triangle are the ratio for cos?

anonymous · Answer

So do you just want someone to give you the answer or do you want help?

anonymous · Answer

It seems that you are just fishing for an answer. Good luck.

anonymous · Answer

the answer is 0.470588235

anonymous · Answer

Sorry, I was away from my computer @Paynesdad!

anonymous · Answer

Not exactly. But that is the approximate answer.

anonymous · Answer

I want to know how to get that answer. Besides I need a fraction, lolz

anonymous · Answer

cos = adjacent/hypotenuse

mathstudent55 · Answer

|dw:1375646681317:dw|

anonymous · Answer

$$\cos (\Theta) = \frac{-15}{17} = \cos^{-1}(\frac{-15}{17})$$

so draw a triangle 
|dw:1375646844403:dw|

Use the Pythagorean solve for opposite 
and $$\sin (\Theta) = \frac{opposite}{Hypotenuse}$$

anonymous · Answer

OH, nice visual

mathstudent55 · Answer

@ilfy214 Do you understand my figure above? You can get your answer directly from it.

anonymous · Answer

-15/17

mathstudent55 · Answer

Your problem has two parts.
1. What is arccos of (-15/17)?
2. What is sin of angle in part 1?

anonymous · Answer

I'm sorry. that was cos. 8/17

mathstudent55 · Answer

Look in my figure. I drew the side of 15 as -15 in the graph so you see the angle whose cosine in -15/17.

mathstudent55 · Answer

Now take the sine to get 8/15.
I see that you got it.
Great!

anonymous · Answer

Thanks! But you mean 8/17, right? :)

mathstudent55 · Answer

yes, 8/17

anonymous · Answer

Nice job!

anonymous · Answer

THANK YOU EVERYONE!