Question

The problem is:
Solve each of the following equations over the interval [0,2Pi).

2sin^2 x - 1 = 0

The answers are:

Pi/4, 3Pi/4, 5Pi/4, 7Pi/4

I know how to get the first two answers, but I'm not sure how you get the last two answers, since sin would be negative in quadrants 3 and 4.

Much help appreciated. Thanks.

Jun 4, 2009

bobpursley

Well, remember that a square root has both +- roots.

Jun 4, 2009

Wouldn't the last two answers be negative then?

Jun 5, 2009

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