# Trig. Finding the general solution

• December 16th 2008, 05:14 PM
akpolish
Trig. Finding the general solution
2 cos x = sec x

• December 16th 2008, 05:23 PM
chabmgph
Quote:

Originally Posted by akpolish
2 cos x = sec x

Hint: $\sec x = \frac{1}{\cos x}$

Try to solve for $\cos x$ and see.
• December 16th 2008, 05:25 PM
akpolish
Thank you for the hint but I still don't understand.
• December 17th 2008, 04:36 PM
chabmgph
Quote:

Originally Posted by akpolish
2 cos x = sec x

Quote:

Originally Posted by akpolish
Thank you for the hint but I still don't understand.

$2 \cos x = \sec x$
$2 \cos x =\frac{1}{\cos x} \text{ \; \; \; \; (}\cos x \neq 0$)
$2 \cos^2 x =1$
$\cos^2 x =\frac{1}{2}$
$\cos x =\pm\frac{\sqrt{2}}{2}$

Now see if you can find the angles which gives you these value.