integral sin(x) dx = -cos(x) + constant

-1/2 e^(-i x) - e^(i x)/2 + constant

-1 + x^2/2 - x^4/24 + O(x^6) (Taylor series)

integral_0^π sin(x) dx = 2

integral_0^(2 π) (sin^2(x))/(2 π) dx = 1/2 = 0.5