`intcos^(-1)((1-x^(2))/(1+x^(2)))dx=?`A. `2xtan^(-1)x+log(1+x^(2))+C`B. `-2xtan^(-1)x-2log(1+x^(2))+C`C. `2xtan^(-1)x-log(1+x^(2))+C`D. none of these

`intcos^(-1)((1-x^(2))/(1+x^(2)))dx=?`A. `2xtan^(-1)x+log(1+x^(2))+C`B

1.	`intcos^(-1)((1-x^(2))/(1+x^(2)))dx=?`A. `2xtan^(-1)x+log(1+x^(2))+C`B. `-2xtan^(-1)x-2log(1+x^(2))+C`C. `2xtan^(-1)x-log(1+x^(2))+C`D. none of these
Answer» Correct Answer - C Put `x=tant anddx=sec^(2)tdt`. Then, `I=intcos^(-1)((1-tan^(2)t)/(1+tan^(2)t))sec^(2)tdt=intcos^(-1)(cos2t)sec^(2)tdt` `=2intunderset(I)(t)underset(II)(sec^(2))tdt`.