The question turns out to only be part of my frustration. I am new to Mathematica but am solving a real but deceptively simple model.
When I use Integrate, I get an enourmous number of terms and conditionals, some imaginary, yet manual integration does not present these alternatives. I need to surpress some of the machinations within Mathematica that are not relevant to my solvution.
When I turn to DIntegrate, after a few terms in an expansion, I get a complex error message. None of my attempts at using the suggestions resulted in an improvement. I asked someone, and he suggested decreasing my accuracy goal setting. This worked whereas none of the suggestions by Mathematica did. The actual error message is below in quotes.
"NIntegrate::eincr: The global error of the strategy GlobalAdaptive has increased more than 2000 times. The global error is expected to decrease monotonically after a number of integrand evaluations. Suspect one of the following: the working precision is insufficient for the specified precision goal; the integrand is highly oscillatory or it is not a (piecewise) smooth function; or the true value of the integral is 0. Increasing the value of the GlobalAdaptive option MaxErrorIncreases might lead to a convergent numerical integration. NIntegrate obtained 0.143967 and 0.0000346605 for the integral and error estimates."
I included the output because I do not understand how this output is related to the final statement in the quote: NIntegrate obtained 0.143967 and 0.0000346605 for the integral and error estimates.
I would like someone to point me toward a reference in which I can understand the vocabulary and consequences to implementing a workable solution using Mathematica. If I need to decrease my accuracy, how to I know how much my accuracy is being degraded and by how much?
Regards and thanks for any help.