Tan inverse X + tan inverse Y + tan inverse z=pie prove that X+Y+Z=xyz
​

see explanation

Step-by-step explanation:

Given

x + y + z = π

let

x = A , y = B , z = C , so

x = tanA, y = tanB , z = tanC

Substituting values

A + B + C = π  ( subtract C from both sides )

A + B = π - C ( take tan of both sides )

tan(A + B) = tan(π - C) = - tanC ( expand left side using addition identity for tan )

= - tanC ( multiply both sides by 1 - tanAtanB )

tanA + tanB = - tanC( 1 - tanAtanB) ← distribute

tanA+ tanB = - tanC + tanAtanBtanC ( add tanC to both sides )

tanA + tanB + tanC = tanAtanBtanC , that is

x + y + z = xyz

the answer to the expression is 83