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I have a simple question, for the specific project I am working on I would like mathematica to not evaluate extremely small decimals (of the order of ~10^-90) to zero. I would like a scientific notation return. When I evaluate similar expressions into WolframAlpha I receive a non-zero result. For an example of a specific evaluation which returns non-zero in wolfram, and zero in mathematica:

Mathematica:

In[219]:= Integrate[dNitrogen, {v, 11000, Infinity}]

Out[219]= 0.

Compared to WolframAlpha:

I've tried searching around myself but oddly enough have only found solutions to the opposite of my problem -Those wanting when mathematica evaluates the small number to print as zero, this seems to involve some use of the Chop function.

Thanks for help/suggestions.

eclement
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    Since we have no idea what your dNitrogen expression is we are limited in pinpointing the problem. Since you are getting a decimal point on output then you have buried somewhere inside your dNitrogen one or more numbers with a decimal point and you have only given it a few digits of precision. Mathematica tracks the precision of every part of a calculation and if you say dNitrogen=0.5 Mathematica assumes you only have 1 digit of precision. Increase precision of all constants constants with decimal points so that every one has 100+ digits of precision and see how this changes. Show the results – Bill Jul 20 '14 at 03:19

1 Answers1

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You should use NIntegrate instead of Integrate. By default it will give you the precision you're wanting, and it's also configurable through the PrecisionGoal parameter (and other parameters, see the NIntegrate docs for details).

cobbal
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