3.5.2.5.37 sin_integral

Definition:

Si = sin\_integral(x) evaluates

Si(x)=\int_0^x\frac{\sin u}udu

The approximation is based on several Chebyshev expansions.

For more information please review the s13adc function in the NAG document.

Parameters:

x (input, double)
The argument x of the function.
Si (output, double)
the approximation of the formula Si(x)=\int_0^x\frac{\sin u}udu