f'(x) = π/2 2x sin(π/2 x²) + π/2 sin(π/2 x) + π/2 x cos(π/2 x)
f'(x) = πx sin(πx²) + π/2 sin(πx) + πx * cos(πx)
f'(x) = π/2 2x sin(π/2 x²) + π/2 sin(π/2 x) + π/2 x cos(π/2 x)
f'(x) = πx sin(πx²) + π/2 sin(πx) + πx * cos(πx)