SOLUTION: Can you help me with this problem? How to find cscθ, if θ=cos^-1(-4/5)? Thank you.

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Question 1144167: Can you help me with this problem?
How to find cscθ, if θ=cos^-1(-4/5)?
Thank you.
Answer by ikleyn(52798) About Me  (Show Source):
You can put this solution on YOUR website!
.

The fact that  θ=cos^-1(-4/5)  means  that  cos(θ) = -4%2F5  and theta in the angle in QII.


Then  csc(θ) = 1%2Fsin%28theta%29 = 1%2Fsqrt%281-cos%5E2%28theta%29%29 = 1%2Fsqrt%281+-+%28-4%2F5%29%5E2%29 = 1%2Fsqrt%281+-16%2F25%29%29 = 1%2Fsqrt%289%2F25%29 = 1%2F%28%283%2F5%29%29 = 5%2F3.    ANSWER


Notice that the final answer is positive, since both sine and csc functions are positive in QII.