Find sin x/2 if cosx =24/25 in first quadrant



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pramodpandey's profile pic

Posted on (Answer #2)

We have given


`cos(x)=1-2sin^2(x/2)`   ,

it is an identity `cos(2theta)=1-2sin^2(theta)`






`sin(x/2)=sqrt(1/50)`   ,

Since x is in first quadrant ,so x/2 also in first quadrant. In first quadrant all trigonometric ratios are positive.



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susank7780's profile pic

Posted on (Reply #1)

When you simplify the fraction you get 1/50 not 1/100.How are you getting 1/100?

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