Determine the zeros of the function y=-2cos(2x)+1
two zeros:
Determine the zeros of the function y = 3sin(x-pi/4)
-2cos(2x) + 1 = 0
-2 cos (2x) = -1
cos (2x) = 1/2
Note
cos (A) = 1/2 at x= 60° and x = 300°
So
A = 2x = 60 and A = 2x = 300
x= 30° = pi/ 6 x = 150° = 5pi/6
3sin (x - pi/4) = 0 divide both sides by 3
sin ( x - pi/4) = 0
sin A = 0 at A = 0 and A =pi
A = x -p/4 = 0 A = x - pi/4 = pi
x = pi/4 x = pi + pi/4 = 5pi/4