ExpIntegralEi
gives the exponential integral function .
Details
- Mathematical function, suitable for both symbolic and numerical manipulation.
- , where the principal value of the integral is taken.
- ExpIntegralEi[z] has a branch cut discontinuity in the complex z plane running from -∞ to 0.
- For certain special arguments, ExpIntegralEi automatically evaluates to exact values.
- ExpIntegralEi can be evaluated to arbitrary numerical precision.
- ExpIntegralEi automatically threads over lists.
- ExpIntegralEi can be used with Interval and CenteredInterval objects. »
Examples
open allclose allBasic Examples (5)
Plot over a subset of the reals:
Plot over a subset of the complexes:
Series expansion around the branch point at the origin:
Series expansion at Infinity:
Scope (37)
Numerical Evaluation (5)
Evaluate numerically to high precision:
The precision of the output tracks the precision of the input:
ExpIntegralEi can take complex number inputs:
Evaluate ExpIntegralEi efficiently at high precision:
Compute worst-case guaranteed intervals using Interval and CenteredInterval objects:
Or compute average-case statistical intervals using Around:
Compute the elementwise values of an array:
Or compute the matrix ExpIntegralEi function using MatrixFunction:
Specific Values (3)
Visualization (3)
Function Properties (10)
ExpIntegralEi is defined for all real values except 0:
ExpIntegralEi takes all real values:
ExpIntegralEi has the mirror property :
ExpIntegralEi is not an analytic function:
ExpIntegralEi is not monotonic over the reals:
However, it is monotonic over each half-line:
ExpIntegralEi is not injective:
ExpIntegralEi is surjective:
ExpIntegralEi is neither non-negative nor non-positive:
ExpIntegralEi has both singularity and discontinuity at zero:
ExpIntegralEi is neither convex nor concave:
Integration (3)
Indefinite integral of ExpIntegralEi:
Definite integral of a function involving ExpIntegralEi:
Series Expansions (3)
Taylor expansion for ExpIntegralEi around :
Plot the first three approximations for ExpIntegralEi around :
Find series expansion at infinity:
Give the result for an arbitrary symbolic direction:
ExpIntegralEi can be applied to power series:
Function Identities and Simplifications (3)
Use FullSimplify to simplify expressions containing exponential integrals:
Function Representations (4)
ExpIntegralEi can be represented as a DifferentialRoot:
ExpIntegralEi can be represented in terms of MeijerG:
TraditionalForm formatting:
Applications (3)
Properties & Relations (8)
Use FullSimplify to simplify expressions containing exponential integrals:
Obtain ExpIntegralEi from integrals and sums:
Obtain ExpIntegralEi from a differential equation:
Possible Issues (3)
ExpIntegralEi can take large values for moderate‐size arguments:
ExpIntegralEi has a special value on the negative real axis, not obtained as a limit from either side:
A larger setting for $MaxExtraPrecision can be needed:
Text
Wolfram Research (1988), ExpIntegralEi, Wolfram Language function, https://reference.wolfram.com/language/ref/ExpIntegralEi.html (updated 2022).
CMS
Wolfram Language. 1988. "ExpIntegralEi." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/ExpIntegralEi.html.
APA
Wolfram Language. (1988). ExpIntegralEi. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ExpIntegralEi.html