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Evaluate : `(i) int_(0)^(pi//4)sqrt(1+sin2x) dx` `(ii) int_(0)^(pi//2)sqrt(1+cos2x) dx`

Answer» `(i) int_(0)^(pi//4)sqrt(1+sin2x)dx=int_(0)^(pi//4)sqrt(cos^(2)x+sin^(2)x+2sinxcosx)dx`
`=int_(0)^(pi//4)(cosx+sinx)dx=[sinx-cosx]_(0)^(pi//4)=1`.
`(ii) int_(0)^(pi//2)sqrt(1+cos2x)dx=int_(0)^(pi//2)sqrt(2cos^(2)x)dx`
`=sqrt(2)int_(0)^(pi//2)cosxdx=sqrt(2)[sinx]_(0)^(pi//2)=sqrt(2)`.


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