solve 2cos^2(x) - cos(x) = 0 on the interval 0<=x < 180
we start y factoring and solving for each equation:
cos(x) (2cos(x) - 1) = 0
this means:
cos(x) = 0 and cos(x) = 1/2
from the first equation we get: x = 90
and from the second equation using the known trigonometric triangles we get
x = 60
therefore x = 60, 90 in the interval asked.
DS
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