Approximate ∫abf(x)dx≈h3[f(x0)+4∑i=1n/2f(x2i−1)+2∑i=1n/2−1f(x2i)+f(xn)]\int_a^b f(x) dx \approx \frac{h}{3} \left[ f(x_0) + 4\sum_{i=1}^{n/2} f(x_{2i-1}) + 2\sum_{i=1}^{n/2 - 1} f(x_{2i}) + f(x_n) \right]∫abf(x)dx≈3h[f(x0)+4∑i=1n/2f(x2i−1)+2∑i=1n/2−1f(x2i)+f(xn)] for even nnn.
