Integration problem

Discussion in 'FAC & Stats Pack' started by msmat999, Aug 25, 2012.

  1. msmat999

    msmat999 Member

    I was just wonder how I would integrate 2cxexp[-cx^2] where c is a constant. Would I want to use integration by parts? Along the lines of;

    u = 2cx => du/dx = x

    dv = exp[-cx^2]
     
  2. tiger

    tiger Member

    Yes to integration by parts, but I would say
    u=cx^2
    du= 2cxdx
    2cxexp[-cx^2]
    becomes
    exp[-u]du
     
  3. John Lee

    John Lee ActEd Tutor Staff Member

    We'd use integration by substitution with u = -cx².

    In which case du/dx = -2cx. Hence "du = -2cx dx"

    So the integral would become -exp(u) which would integrate to -exp(u) = -exp(-cx²).
     

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