Question

Solve equation for 0 < x < 2pi

Answer 1

`\sqrt2\cos x-1=0`

`\sqrt2\cos x=1`

`\cos x=\frac1{\sqrt2}`

This occurs twice in the interval
`0\le x\le2\pi`, when
`x=\frac\pi4` and
`x=\frac{3\pi}4`.