Question

cos x(2cos x+1)=1

Answer 1

if you need to solve this then rewrite it as

\[2\cos^2(x) + \cos(x) - 1 = 0\]

which factors to

\[(2\cos(x) - 1)(\cos(x) + 1) = 0\]

so now you are solving

2cos(x) - 1 = 0

and

cos(x) + 1 = 0

hope it helps

Answer 2

oops forgot to say, this is an equation that is reducible to a quadratic... so can be factored.