Equation

Printable View

March 11th 2011, 10:19 AM
Critter314

Equation

How to prove?
$cos 2x + cos x = sin^2 x$
All Ive got so far is $cos^2 x - sin^2 x + cos x = sin^2 x$
March 11th 2011, 10:23 AM
emakarov

Let's see, cos(2 * 0) + cos(0) = 2. Hmm...
March 11th 2011, 10:36 AM
TheChaz

It should read "solve", and we've already addressed this (7 minutes ago) at mymathforum!

I'm ok with you replying in either place... Obviously ;)
March 11th 2011, 06:40 PM
Prove It

Now substitute $\displaystyle \sin^2{x} = 1 - \cos^2{x}$ to get a quadratic equation in $\displaystyle \cos{x}$ , which you will be able to solve.
March 12th 2011, 03:54 PM
TheChaz

Yeah, I said that already! ;)

All times are GMT -8. The time now is 07:47 AM.