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Integral not evaluating

Posted 10 years ago

enter image description here

I tried posting a screenshot above but I'm not sure if it works. I'm trying to evaluate an integral from -inf to inf. After doing Assume[] and my integral, it just outputs my integral without evaluating it. Please help!

POSTED BY: Caleb Spires
4 Replies

If you post your actual code, instead of pictures, that would eliminate the guesswork (although the guesswork thus far looks like it is on target).

POSTED BY: Daniel Lichtblau
Posted 10 years ago

Why doesn't it work like I have it? This is how my teacher showed us to do it. enter image description here

POSTED BY: Caleb Spires
Posted 10 years ago

Presumably because the tiny little unclear character that I can't quite see isn't an "ordinary variable" but is a desktop published something.

POSTED BY: Bill Simpson
Posted 10 years ago

This?

In[1]:= Assuming[{s > 0},
  Integrate[Exp[-(x - xbar)^2/(2 s^2)], {x, -Infinity, Infinity}]]

Out[1]= Sqrt[2 [Pi]] s

Note: Using > implies, without really being obvious about it, that this also means "element of the Reals."

I am assuming, based on the error message immediately before your Integral, that you have fallen into the "I must desktop publish my Mathematica input" trap and that everything, no matter how desktop published it is, can be expected to work like any other simple ordinary variable. That trap bites people again and again and again and ... and does not seem to be able to be resisted.

POSTED BY: Bill Simpson
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