Question

Value of sin 74° by sin (a+b)

Answer 1

it can be split into sin(36+18)= sin36cos18+cos36sin18 and put these values sin18=(√5-1)/4 and cos18 is( (10+2✓5)^1/2)/4
cos36= (✓5+1)/4 and sin36= ((10-2✓5)^1/2)/4 put these values and get your ans