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From: Steven Lord on 27 Jun 2010 22:39

"Angie" <angie11tr(a)yahoo.com> wrote in message
news:i03aa5$t52$1(a)fred.mathworks.com...
> Hi,
>
> Is there a way to solve the following definite integral? My integrand is
> symbolic:
>
> myintegrand = @(x) x*normcdf(x,1,0);
> int(myintegrand,x,0,1)
>
> Matlab says:
> Warning: Explicit integral could not be found. ans =
> int(x*normcdf(x, 1, 0), x = 0..1)
>
> Basically, it does not give me an answer. I also tried "erfc" with no
> luck.

NORMCDF is a function from Statistics Toolbox that's defined for _numeric_
inputs, not symbolic.

Using the expression from the documentation for NORMCDF, you can find the
value of your integral:

syms x t
integralBody = exp(-t^2/2);
symbolicNormcdf = (1/sqrt(2*sym(pi)))*int(integralBody, -Inf, x);
myintegrand = int(x*symbolicNormcdf, 0, 1)

VPA this expression to obtain a numeric representation of the result.

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
To contact Technical Support use the Contact Us link on
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