SOLUTION: Determine cos θ to three decimal places when sin θ= 6/square root 61 and θ is an angle in second quadrant. thanks

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Question 1165802: Determine cos θ to three decimal places when sin θ= 6/square root 61 and θ is an angle in second quadrant.

thanks
Answer by ikleyn(52855) About Me  (Show Source):
You can put this solution on YOUR website!
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You are given  sin%28theta%29 = 6%2Fsqrt%2861%29.


Then  cos%28theta%29 = +/- sqrt%281-sin%5E2%28theta%29%29 = +/- sqrt%281-36%2F61%29 = +/- sqrt%28%2861-36%29%2F61%29%29 = +/- sqrt%2825%2F61%29 = +/- 5%2Fsqrt%2861%29.


Since  theta  is in QII, the sign of the cosine is  " - ",  so the answer is  - 5%2Fsqrt%2861%29.


Use your calculator.

Solved.