" 4."tan^(-1)(1)/(2)+tan^(-1)(1)/(3)=(pi)/(4)

tan^(-1)((1)/(2))+tan^(-1)((1)/(3))=(pi)/(4)|0tan(1)+tan(1)

tan(2tan^(-1)((1)/(3))-(pi)/(4))

tan^(-1)(x/2)+tan^(-1)(x/3)=(pi)/(4)

tan^(-1)((3)/(n))+tan^(-1)((4)/(n))=(pi)/(2)

Prove that: tan^(-1)(1)/(7)+tan^(-1)(1)/(13)=tan^(-1)(2)/(9)tan^(-1)+tan^(-1)(1)/(5)+tan^(-1)(1)/(8)=(pi)/(4)tan^(-1)(3)/(4)+tan^(-1)(3)/(5)-tan^(-1)(8)/(19)=(pi)/(4)tan^(-1)(1)/(5)+tan^(-1)(1)/(7)+tan^(-1)(1)/(3)+tan^(-1)(1)/(8)=(pi)/(4)cot^(-1)7+cot^(-1)8+cot^(-1)18=cot^(-1)(1)/(13)

Prove that tan^(-1)""(3)/(4)+tan^(-1)""(3)/(5)-tan^(-1)""(8)/(19)=(pi)/(4)

4tan^(-1)((1)/(5))=tan^(-1)((1)/(70))+tan^(-1)((1)/(99))+(pi )/(4)

tan^(-1)(tan\ (3pi)/(4))

Solve tan^(-1)x -"tan"^(-1)(1)/(4)=(pi)/(4) .