Tentukan turunan kedua dari cos²(2x-1)​

f(x) = cos² (2x – 1)

f'(x) = 2 cos (2x – 1) (-sin (2x – 1) (2)

f'(x) = –2 sin (4x – 2)

f''(x) = –2 cos (4x – 2) (4)

f''(x) = –8 cos (4x – 2)