SOLUTION: Given that cos t = 8/9 and that P(t) is a point in the fourth quadrant, find sin t. sin t =

Algebra ->  Trigonometry-basics -> SOLUTION: Given that cos t = 8/9 and that P(t) is a point in the fourth quadrant, find sin t. sin t =      Log On


   

Question 1031224: Given that cos t = 8/9 and that P(t) is a point in the fourth quadrant, find sin t.
sin t =
Answer by ikleyn(52834) About Me  (Show Source):
You can put this solution on YOUR website!
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Given that cos t = 8/9 and that P(t) is a point in the fourth quadrant, find sin t.
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Since cos(t) = 8%2F9, you have 

sin%5E2%28t%29 = 1+-+cos%5E2%28t%29 = 1+-+%288%2F9%29%5E2%29+=+%7B%7B%7B1+-+64%2F81 = 81-64%29%2F81 = 17%2F81.

Hence, sin(t) = +/- sqrt%2817%29%2F9.

Now, what sign,  "+"  or  "-",  to choose? 

Since P(T) is in QIV, what sign for sin(t) will you choose?

Comment from student: Thanks so much for the help! By the way, I'm thinking that the sign would be negative? 

My response:  you are right!  Hope next time you will be able to solve similar problems on your own.  Good luck!!!