Error in evaluation of definite integral

[robclewley]

I can't get a meaningful output for the integration of a function that does not have an explicit antiderivative: f(x) = x*x*sqrt(ln(1+x)) for x = 1.. 3. Maple confirms that the value is 9.40202759 but pocketCASpro 2.5 on my iphone doesn't even give me a real number when I surround the expression with simplify(int(<expr>)). Instead, it gives the function

(-514*sqrt(ln(x+1))-204*sqrt(ln(x+1)) ) / 3

This is absurd since the definite integral has to be a real value! If I don't use simplify() I get an unevaluated integral returned that has a vastly more complicated looking integrand than my original integrand ... not sure if it's been correctly manipulated or not.

I assume this is a full on bug. Any thoughts or help please?

[MrMage]

Hello,

You are right, this seems to be a bug. I'll forward it to the developer of the CAS.

To numerically integrate functions without an antiderivative, please use the nInt() function.

Cheers

Daniel

[MrMage]

Hi Rob,

An update on this issue: In the next version, PocketCAS still won't be able to solve the integral symbolically. It will still give a more complex version of the integral, but it will continue to be an integral. In order to solve this integral and similar ones, just keep using nInt().

Greetings

Daniel