1.

`int_(0)^(pi//2) sec x log (sec x+tan x) dx` is equal toA. `(1)/(2)[log(1+sqrt2)]^(2)`B. `[log(1+sqrt2)]^(2)`C. `(1)/(2)[log(sqrt2-1)]^(2)`D. `[log(sqrt2-1)]^(2)`

Answer» Correct Answer - A
Let ` int _(0)^(pi//4) sec x log (sec x + tan x) dx ` ,
Put log `(sec x + tan x) = t rArr sec x dx = dt`
` :. l = int _(0)^(log(sqrt(2)+1))t dt = [ (t^(2))/2]^(log(sqrt(2)+1))= ([log (sqrt(2)+1)]^(2))/2 `


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