SOLUTION: Can someone PLEASE help me with this problem? Find the exact value of cos(2theta) given csc(theta)=(11/8) and 0<theta<(pi/2) Thank you!

Question 607038: Can someone PLEASE help me with this problem?
Find the exact value of cos(2theta) given csc(theta)=(11/8) and 0 Thank you!
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
csc(x) = 11/8

1/sin(x) = 11/8

sin(x) = 8/11

sin^2(x) = (8/11)^2

sin^2(x) = 64/121

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cos(2x)

1-2sin^2(x)

1 - 2*(64/121)

1 - 128/121

121/121 - 128/121

(121 - 128)/121

-7/121

So

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