" 15.",tan^(-1)(1-x^(2))/(1+x^(2))

tan^-1((2x)/(1-15x^2))

Differentiate tan ^(-1) ((8x)/(1-15x^(2))) w.r.to tan ^(-1) ((2xsqrt(1-x^(2)))/(1-2x^(2)))

If : x = tan25^(@), "then": (tan 155^(@) - tan 115^(@))/(1 + tan 155^(@) * tan 115^(@))= A) (1-x^(2))/(2x) B) (1+x^(2))/(2x) C) (1+x^(2))/(1-x^(2)) D) (1-x^(2))/(1+x^(2))

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

Simplify 2"tan"^(-1)x+"sin"^(-1)((2x)/(1+x^(2))) in terms of "tan"^(-1)x .

If x gt 1 then 2tan^(-1)x - tan^(-1) ((2x)/(1-x^(2))) =______.

Prove the following: 2tan^(-1)x=tan^(-1)((2x)/(1-x^(2))),-1ltxlt1

sin^(-1)((1-tan^(2)x)/(1+tan^(2)x))