Calculating the fixed integral value of the one-element function by Gaussian method

This page uses the Gaussian method to calculate the definite integral of a unary function. The
accuracy is not as good as the dragon method, but it is faster and sometimes
the accuracy is satisfactory. Enter the function expression in the edit box following f(x)= below.
See the syntax of the function expression.

Function Expression page, also enter the lower and upper limits of the integration
x1 and x2 (x1<x2) below. The range of the argument is generally the input number, but you can also
enter the constant. Expression, input method of constant expression.

Constant Expressions page. Then click on the "Start Integration" button, the curve
of the given function within the given range will be displayed and the integral value will be given.