Verified answer

Use:

sin u - sin v = 2 cos[(u + v)/2] sin[(u - v)/2]

so sin(4θ) - sin(6θ) = 2 cos(5θ)sin(-θ)=0

let k be an integer.

cos(5θ)=0 --> 5θ= k*pi/2 --> θ=k*pi/10

sin(-θ)=-sin(θ)=0 --> θ=k*pi

ur in my precal class arent u lol cuz ur asking all the same questions im searching for