
Dayv O. answered 12/06/21
Caring Super Enthusiastic Knowledgeable Trigonometry Tutor
tan1 of a number is an angle, need to use sin(A+B) formula
given tan-1u is angle , the angle is part of right triangle and has opposite side u and adjacent side 1.
sin(tan-1u)=u/√(1+u2) and cos(tan-1u)=1/√(1+u2)
same idea with v
correction
sin(tan^-1(u)+tan^-1(v))=[u/√(1+u2) ]*[(1/√(1+v2)]+[v/√(1+v2)]*[(1/√(1+u2)]
=[u+v]*[(1+u2)*(1+v2)]-(1/2)