gives the exponential integral function .


  • 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.
Introduced in 1988