Prove that sec4x−tan4x≡1+2tan2x\sec^4 x - \tan^4 x \equiv 1 + 2\tan^2 xsec4x−tan4x≡1+2tan2x.
Hence solve, for 0°≤x≤360°0° \leq x \leq 360°0°≤x≤360°, the equation
sec4x−tan4x=3\sec^4 x - \tan^4 x = 3sec4x−tan4x=3