�@
Numerical Integration

---

You can obtain quadrature of a data series (including plotted function) with trapezoidal rule. If you have selected "spline interpolation", the integral of the interpolating curve is given.
If lower limit (a) or upper limit (b) is not correspond to a data point, f(a) or f(b) is calculated with linear interpolation. Also, the area between line (data points) and Xb-axis is painted with lightened color of the line from a to b. If you do not want to have it painted, uncheck the [Paint integrated region].