Question

If sin A = √3/2 and tanB = √3 prove that cos(a+b)=1 where a and b are acute angles

Answer 1

sin A=√3/2

sinA=sin60

A=60°


tanB=√3

tanB=tan60°

B=60°

cos (A+B)=cos(60+60)=cos120°


cos120=cos(180-60)=-cos60=-1/2(not 1)