SOLUTION: suppose theta is an angle in standard position whose terminal side lies in quadrant iii. If the sin theta= 15/17 what is the cos theta?

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Question 973152: suppose theta is an angle in standard position whose terminal side lies in quadrant iii. If the sin theta= 15/17 what is the cos theta?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


You have described an impossible situation. Sine is negative in the third quadrant. However, I'm going to proceed assuming the highly likely event that you meant to type .



Square both sides:



Use the Pythagorean Identity:



Algebra and arithmetic:



Take the square root:



But cosine is negative in QIII, so discard the positive root:



Of course all of this is valid ONLY to the extent that my assumption about your typing error was correct.

John

My calculator said it, I believe it, that settles it