Find all solutions of cos x = 1/2 in the interval [-3pi,3pi].

Could someone explain how to solve this? Cheers.

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- Jan 17th 2009, 07:45 AMHarisHyperbolic function?
Find all solutions of cos x = 1/2 in the interval [-3pi,3pi].

Could someone explain how to solve this? Cheers. - Jan 17th 2009, 07:57 AMJester
First I would graph the function on the interval $\displaystyle [-3\pi,3\pi]$ to find the number of times $\displaystyle \cos x = \frac{1}{2}$. From th symmetry of the cosine curve and knowing that one answer is $\displaystyle x = \frac{\pi}{3}$ should get you the rest.