Question

find the value of cos2 theta ,when sin theta =9/10

Answer 1

cos 2theta= 1-sin^2theta
=1-(9/10)^2
=1-(81/100)
=(100-81)/100
=19/100
=0.19
Therefore the value of cos2theta is 19/100 when sin theta=9/10.
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Answer 2

good afternoon,

here is your answer:-

thanks