Question

please answer this question​

Answer 1

Answer:

sinC - sinD = 2cos(C+D/2)*sin(C-D/2)

Step-by-step explanation:

sin3A + sin2A - sinA

(sinC + sinD = 2sin(C+D/2)*cos(C-D/2))

(sin3A + sin2A) - sinA

=2 sin(5A/2)*cos(A/2) - 2sinA/2*cosA/2

=2 cos(A/2) (sin(5A/2) - sin(A/2))

= 2 cos(A/2)(2 cos(3A/2)*sinA)

= 4 sinA*cos(A/2)*cos(3A/2)