How do you find the general solutions for 6cos^2x - cos x - 1 = 0?
1 Answer
Aug 12, 2015
Explanation:
To simplify matters, take
This can be solved by factorisation, as follows.
Now, replacing
cos(x) = 1/2 => x = 2m pi +- pi/6, m in ZZ cos(x) = -1/3
=> x = (2n) pi +- arccos(-1/3), n in ZZ
=> x = (2n+1) pi +- arccos(1/3), n in ZZ