Question

help me

Answer 1

prove \[\tan^{-1} a+\tan^{-1} b=\tan^{-1} (a+b)/(1-ab)\]

Answer 2

do you know the formula of tan(a+b) ?

Answer 3

yes i kn @SerikMB

Answer 4

take both sides by tan so that tan(tan^-1(a)+tan^-1(b))=tan(tan^-1((a+b)/(1−ab))

Answer 5

you will get (a+b)/(1−ab) at the right side

Answer 6

then use tan(a+b) formula

Answer 7

actually i know if we wanna to prove we should deal with left hand side so we should prove the left hand please