Skip to main content

ExpIntegralE1

ExpIntegralE1 (z)​

The ExpIntegralE1(z) function returns the exponential integral of z.

If z is real, a real value is returned. If z is complex then a complex value is returned.

The ExpIntegralE1 function was added in Igor Pro 7.00.

Details​

The exponential integral is defined by

E1(z)=∫z∞e−ttdt,(∣arg⁡(z)∣<π).\displaystyle E_{1}(z)=\int_{z}^{\infty} \frac{e^{-t}}{t} d t, \quad(|\arg (z)|<\pi).

References​

Abramowitz, M., and I.A. Stegun, "Handbook of Mathematical Functions", Dover, New York, 1972. Chapter 5.

See Also​

ExpInt, CosIntegral, SinIntegral, HyperGPFQ