Step-by-step explanation:
Given
sin(x) - sin(4x)
= 2 cos (( x + 4x)/2) * sin ( ( x - 4x) / 2))
= 2 cos 5x/2 • sin -3x / 2
= - 2 cos 5x/2 • sin 3x/2
Hope it helps :)❤
