Solve equation for 0 < x < 2pi
\(\sqrt2\cos x-1=0\)\(\sqrt2\cos x=1\)\(\cos x=\dfrac1{\sqrt2}\)This occurs twice in the interval \(0\le x\le2\pi\), when \(x=\dfrac\pi4\) and \(x=\dfrac{3\pi}4\).
