# Hyperbolic function?

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

Could someone explain how to solve this? Cheers.
• January 17th 2009, 07:57 AM
Jester
Quote:

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

Could someone explain how to solve this? Cheers.

First I would graph the function on the interval $[-3\pi,3\pi]$ to find the number of times $\cos x = \frac{1}{2}$. From th symmetry of the cosine curve and knowing that one answer is $x = \frac{\pi}{3}$ should get you the rest.