solve
`tan^-1(1/3) + tan^-1(1/5) + tan^-1(1/7) +tan^-1(1/8)`

Prove that : tan^(-1)(1/2) + tan^(-1)(1/3) = tan^(-1)(3/5) + tan^(-1)(1/4) = pi/4

tan^(-1)(-1)=-tan^(-1)(1)

Show that tan^(-1) (1/2) +tan^(-1) (1/8) = tan^(-1) (3/4) - tan^(-1)(1/18)

Solve : tan^(-1)( 1/2) = cot^(-1) x + tan^(-1)( 1/7)

Prove that: tan^(-1)(1/5)+tan^(-1)(1/7)+tan^(-1)(1/3)+tan^(-1)(1/8)=pi/4

Solve the following equation for x : tan^(-1)(1/4)+2tan^(-1)(1/5)+tan^(-1)(1/6)+tan^(-1)(1/x)=pi/4

Solve the following equation for x : tan^(-1)(1/4)+2tan^(-1)(1/5)+tan^(-1)(1/6)+tan^(-1)(1/x)=pi/4

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

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

The number of integral values of x satisfying the equation tan^(-1) (3x) + tan^(-1) (5x) = tan^(-1) (7x) + tan^(-1) (2x) is ____