Question

2sin^2x-cosx-1=0

my answer have to be redians

Answer 1

\(\bf 2sin^2(x)-cos(x)-1=0\qquad \textit{recall that}\quad sin^2(\theta)=1-cos^2(\theta)\\ \quad \\
2sin^2(x)-cos(x)-1=0\implies 2[1-cos^2(x)]-cos(x)-1=0\\ \quad \\
-2cos^2(x)-cos(x)-1+2=0\)

tis a quadratic, so factor it likewise