Euler method - Wikipedia
https://en.wikipedia.org/wiki/Euler_methodIllustration of the Euler method. The unknown curve is in blue, and its polygonal approximation is in red. In mathematics and computational science, the Euler method (also called forward Euler method) is a first-order numerical procedure for solving ordinary differential equations (ODEs) with a given initial value.
Euler–Maclaurin formula - Wikipedia
https://en.wikipedia.org/wiki/Euler–Maclaurin_formulaIn mathematics, the Euler–Maclaurin formula is a formula for the difference between an integral and a closely related sum.It can be used to approximate integrals by finite sums, or conversely to evaluate finite sums and infinite series using integrals and the machinery of calculus.For example, many asymptotic expansions are derived from the formula, and Faulhaber's formula for the …