Question

cosx sinx -sinx=0

Answer 1

i solve it and get 3 answer but in the back of the book, it ony gave 2 answer.

Answer 2

cosx sinx -sinx=0
sinx(cosx - 1) = 0
sinx = 0 or cosx = 1

within 0 ≤ x ≤ 360°

from sinx = 0 , x = 0 , 180° , 360°
from cosx = 1 , x = 0 , 360°

so x = 0 , 180°, 360°

Answer 3

Usually both 0 and 360 are not in the domain, so the book probably only lists 0 and 180 as solutions.