Question

The value of sin 50° - sin 70° + sin 10° is equal to
(A) 1 (C)1/2
(B)0 (D) 2​

Answer 1

Answer:

Given, sin 50 - sin 70 + sin 10

= sin(60 - 10) - sin(60+10) + sin 10

Formula is Sin(a-b) = sin a cos b- cos a sinb, Sin(a+b) = sin a cos b + cos a sinb

= Sin(60) Cos(10) - Cos(60)Sin(10) - (Sin(60)Cos(10) + Cos(60)Sin(10)) + Sin(10)

= -2*Cos(60) Sin(10) + Sin(10)

= -2*(1/2) * Sin(10) + Sin(10)

= 0

Hope this helps!