Giải các pt sau
1, Sin\(^4\)x + sin\(^4\)(x+\(\frac{\pi}{4}\)) = \(\frac{3}{4}\)
2, Cos\(\frac{x}{2}\) + 2 cos\(^2\)(2x-\(\frac{\pi}{8}\)) =1
3, Sin3x+1=2sin\(^2\)( \(\frac{x}{2}\)+ \(\frac{\pi}{6}\))
4, Sin\(^4\)2x + cos\(^4\)2x =\(\frac{5}{8}\)
5, Cos (3x-\(\frac{\pi}{6}\)) -cos ( 3x + \(\frac{\pi}{6}\)) = \(\frac{\sqrt{2}}{2}\)