Question

find sin^-1 2/3 + sin^-1 √5/3​

Answer 1

Answer:

sin^-1 2/3 = a , sin^-1 √5/3 = b

(we convert sin^-1 to cos^-1

and then use cos(a-b))

Let sin^-1 2/3 = a

sin^-1 a = 2/3

cos a=√1-sin^2a

= √1-(2/3)^2

= √1-4/9 = -5/9

and solve 2nd cos like this