How do I solve this integral numerically in MATLAB using Simpson's 3/8 rule?

[arslan894]

i am making a MATLAB model of cam follower interaction for measureing friction but need help with this integral
f(x) = ∫e^(1-(x^2)/(b^2))dx the limits are -b to b , take the value of b = 3
when i used the ( int )function in MATLAB it tells that the explicit answer doesn't exist ,so how to solve this in MATLAB ?
i used simpsons 3 8 rule to find the answer on paper but how to find it in MATLAB ?

 

[lurflurf]

That is easily done in terms of erf(x/b) or if the limits are -b to b in terms of erf(1)
where erf(1)~0.8427007929497148693412206350826092592960669979663029084599
I do not know how good matlabs erf function is (http://www.mathworks.com/help/techdoc/ref/erf.html), but it should be better than using numerical in integration (http://www.mathworks.com/help/techdoc/ref/quad.html ),