You need to evaluate the solution to the equation `(cos 2x + sin 2x)^2 = 1` , such that:
`cos^2 2x + 2cos 2x*sin 2x + sin^2 2x = 1`
You need to use the formula `cos^2 2x + sin^2 2x = 1` , such that:
`1 + 2cos 2x*sin 2x = 1`
Reducing like terms yields:
`2cos 2x*sin 2x = 0`
You need to use the double angle formula such that:
`2cos 2x*sin 2x = sin 4x`
`sin 4x = 0 => 4x = 0 => x = 0`
`sin 4x = 0 => 4x = pi => x = pi/4`
Hence, the solution to the equation, in `[0,2pi)` , are `x = 0, x = pi/4.`
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