Touba M. answered 05/13/21
B.S. in Pure Math with 20+ Years Teaching/Tutoring Experience
Hi,
When ask you change to product it means you need to have only product
sin(6x)-sin(3x)
you need to know this formula: sin a - sin b = 2 sin ( a - b )/2 * cos ( a + b )/2
now replace given information to this property
sin(6x)-sin(3x) = 2 sin ( 6x - 3x ) / 2 cos ( 6x + 3x )/2
= 2 sin 3/2 x * cos 9/2 x
you see, your answer is ONLY product
I hope it was useful,
Minoo