" 28."(1+x^(2))tan^(-1)x" ."

2tan(tan^(-1)(x)+tan^(-1)(x^(3))), where x in R-{-1,1} is equal to (2x)/(1-x^(2))t(2tan^(-1)x)tan(cot^(-1)(-x)-cot^(-1)(x))tan(2cot^(-1)x)

2"tan"(tan^(-1)(x)+tan^(-1)(x^3)),w h e r ex in R-{-1,1}, is equal to (2x)/(1-x^2) t(2tan^(-1)x) tan(cot^(-1)(-x)-cot^(-1)(x)) "tan"(2cot^(-1)x)

2"tan"(tan^(-1)(x)+tan^(-1)(x^3)),w h e r ex in R-{-1,1}, is equal to (2x)/(1-x^2) t(2tan^(-1)x) tan(cot^(-1)(-x)-cot^(-1)(x)) "tan"(2cot^(-1)x)

Prove that : 1/6tan^(-1)""(2x)/(1-x^2)+1/9tan^(-1)""(3x-x^2)/(1-3x^2)+1/12 tan^(-1)""(4x-4x^3)/((1-6x^2+x^4))= tan^(-1)x

int (e^(x) (x^(2) tan^(-1) x + tan^(-1) x + 1))/( x^(2) + 1) dx is

int_(-1)^(3)(Tan^(-1)""(x)/((x^(2)+1))+Tan^(-1)""(x^(2)+1)/(x))dx=

[ If xgt0 then which of the following is true 1) tan^(-1)xgt(x)/(1+x^(2)), 2) tan^(-1)x=(x)/(1+x^(2)) 3) tan^(-1)xlt(x)/(1+x^(2)), 4) tan^(-1)x!=(x)/(1+x^(2))]