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Fresnel Integrals

  1. Oct 28, 2009 #1
    Hello everyone,

    I am currently dealing with some coupled differential equations. Seems like the result include Fresnel integrals which are easy to be approximated.

    However, I am confused in many ways and I hope some experienced people can answer following:

    1) Normally, we can obtain real numbers' fresnel integral values meaning:

    FresnelS(a) = int(sin(t^2),t , 0, a) where a is a real value.

    What happens if I want to compute some function's fresnel integral?

    FresnelS(t) for example

    2) What is the correct definition of Fresnel integrals. Some say FresnelS= int(sin(t^2)) and others say FresnelS = int(pi/2 * (sin(t^2)))

    3) MATLAB gives a solution including FresnelC and FresnelS. But Matlab does not have any function to deal with fresnels. Anyway, which definition (shown above) does Matlab use?
  2. jcsd
  3. Oct 28, 2009 #2


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    Homework Helper

    There is no standard definition. You just need to know which one is being used each time. Try to figure it out by looking in the documentation or computing a few values.
  4. Oct 28, 2009 #3
    Actually, I still don't know which definition does Matlab use. But -as you said- it should be asy to understand by trying some numeric values. I guess.

    As I solved my own problem, I should answer my own questions.

    i)What happens if I want to compute some function's fresnel integral?
    Answer: Nothing special. For example you have a time vector like t=0.0:0.001:10
    and you can calculate this vector's FresnelS and FresnelC straightforward.

    If you go to MATLAB central, there are many good works to compute Fresnel Integrals in matlab.
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