solve: cos^2(x) + cos(x) = cos2x
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Originally Posted by chopstixdcb solve: cos^2(x) + cos(x) = cos2x Note that . Therefore, your equation becomes . Letting , we end up with the quadratic equation . Can you take it from here?
so now, all i have to do is factor it right?
Originally Posted by chopstixdcb so now, all i have to do is factor it right? If possible; Otherwise, resort to quadratic formula. Also, remember this is a quadratic in terms of , so once you have your solutions, you need to solve and to find the solutions that you're seeking.
oh geez...i feel so dumb right now. okay thanks a lot.
Originally Posted by Chris L T521 If possible; Otherwise, resort to quadratic formula. Also, remember this is a quadratic in terms of , so once you have your solutions, you need to solve and to find the solutions that you're seeking. umm, if you don't mind, can you show me the final steps. for some reason i got non real solution and the other one is cosx=1
. Note that for all . Are there any solutions that don't fit?
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