# Problem recreating example of normal distribution from TI-Nspire [closed]

I have to recreate this formula for calculating normal distribution in Sage:

http ://ntaj.dreamhosters.com/ti.jpg

The picture is from TI-Nspire CAS.

What I'm doing is:

sage: f=1/(0.1*sqrt(2*pi)) * e^((-1/2)*((x-4)/0.1))^2

sage: float(integral(f, 3.9, 4.1))

0.8696735925295498

I can't get the expected result 0.682689 that Nspire gives. Can anyone see why?