apply sum-to-product identity to solve equation for [0,360)

cos(t)-cos3(t)=0

the book says that the answer is 0,90,180,270,360,and 540.

I am getting 0,90,180,and 270, but thought that it was suppose to be less than 360.

sin(2t)-sin(5t)=0 [0,360)

i get -2cos(7t/2)sin(3t/2) and am totally lost on how to find the solutions.Do i divide 0 & 360 by 7/2 & 3/2 to find the solutions?The book has 0,pi/7,3pi/7,2pi/3,4pi/3, and 2pi.

Can anyone help me and explain what i am doing wrong?