1.

`int_(0)^(1)(dx)/(e^(x)+e^(-x))`A. `(1-(pi)/(4))`B. `tan^(-1)e`C. `tan^(-1)e+(pi)/(4)`D. `tan^(-1)e-(pi)/(4)`

Answer» Correct Answer - D
`I=int_(0)^(1)(dx)/((e^(x)+(1)/(e^(x))))=int_(0)^(1)(e^(x)dx)/((e^(2x)+1))=int_(0)^(e)(dt)/((t^(2)+1))`, where `e^(x)=t`.
`=[tan^(-1)t]_(1)^(e)=(tan^(-1)e-(pi)/(4))`.


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