Question 1170384: Solve the equation sin^2x = 3cos^2x.
The value of x that satisfies the equation if x lies in the second quadrant is °?
a. 60 degrees
b. 120 degrees
c. 150 degrees
d. 240 degrees
e. 300 degrees
The value of x that satisfies the equation if x lies in the third quadrant is
°?
a. 60 degrees
b. 120 degrees
c. 240 degrees
d. 300 degrees
e. 315 degrees
Answer by htmentor(1343)   (Show Source):
You can put this solution on YOUR website! Using the identity sin^2x + cos^2x = 1, we have:
1 - cos^2x = 3cos^2x -> 1 = 4cos^2x -> cos^2x = 1/4
Thus, we need to find x such that cosx = +-1/2.
In the 2nd quadrant, cos(120) = -1/2
In the 3rd quadrant, cos(240) = -1/2
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