Prove that: sin^4(pi/8) + sin^4(3pi/8) + sin^4(5pi/8) + sin^4(7pi/8) = 3/2 | Trigonometry

Prove that: sin^4(pi/8) + sin^4(3pi/8) + sin^4(5pi/8) + sin^4(7pi/8) = 3/2 | Trigonometry

Solution: