SOLUTION: Suppose that tan(t)=-12/5 where t is in the second quadrant. Find cos(2t).

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Question 888541: Suppose that tan(t)=-12/5 where t is in the second quadrant. Find cos(2t).
Answer by lwsshak3(11628) About Me  (Show Source):
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Suppose that tan(t)=-12/5 where t is in the second quadrant. Find cos(2t).
You are working with a (5/12/13) reference right triangle in quadrant II
sin(t)=12/13
cos(2t)=1-2sin^2(t)
=-(1-(12/13)^2)
=-(1-144/169)
cos(2t)=-(25/69)