1 = cos^2 (x) + sin^2 (x) = (e^ix + e^-ix )^2 /4 + sin^2 (x) = (e^2ix + e^-2ix )/4 + e^2ln(sin(x)) + 1/2
int_{0} ^ {π/2} {x * prod_{j = 1} ^ {∞} {cos(x / 2^j )}} dx
1 = cos^2 (x) + sin^2 (x) = (e^ix + e^-ix )^2 /4 + sin^2 (x) = (e^2ix + e^-2ix )/4 + e^2ln(sin(x)) + 1/2
a=42
b=7
