Question #e1f68

2 Answers
Dec 26, 2016

sin(tan^-1u+sin^-1v)sin(tan1u+sin1v)

=sin(cot^-1(1/u)+sin^-1v)=sin(cot1(1u)+sin1v)

=sin(csc^-1sqrt(1+1/u^2)+sin^-1v)=sin(csc11+1u2+sin1v)

=sin(csc^-1((sqrt(u^2+1))/u)+sin^-1v)=sin(csc1(u2+1u)+sin1v)

=sin(sin^-1(u/(sqrt(u^2+1)))+sin^-1v)=sin(sin1(uu2+1)+sin1v)

=sinsin^-1((u/(sqrt(u^2+1)))xxsqrt(1-v^2)+sqrt(1-u^2/(u^2+1))xxv)=sinsin1((uu2+1)×1v2+1u2u2+1×v)

=((usqrt(1-v^2))/(sqrt(u^2+1))+v/sqrt(u^2+1))=(u1v2u2+1+vu2+1)

=(usqrt(1-v^2)+v)/sqrt(u^2+1)=u1v2+vu2+1

Dec 26, 2016

=(u sqrt(1-v^2)+v)/sqrt(1+u^2)=u1v2+v1+u2

Explanation:

Let a = tan^(-1)u in Q_1, if u >= 0, and in Q_2 if u <= 0.

sin a = u/sqrt(1+u^2) and cos a= 1/sqrt(1+u^2)

Let b = sin^(-1)v in Q_1, if v >= 0, and in Q_2 if v <= 0.

sin b = v and cos v = sqrt(1-v^2)

In any case, cos a and cos b > 0. sin a < 0, if u < 0.

The given expression is

sin ( a + b ) = sin a cos b + cos a sin b

=(u/sqrt(1+u^2))(sqrt(1-v^2))+(1/sqrt(1+u^2))(v)

=(u sqrt(1-v^2)+v)/sqrt(1+u^2)