When do we use the "n" of nInt or nSolve?

[dekoyl]

On the CAS calculator, it offers "n" versions of the integral and solve: nInt and nSolve. When do we use the "n" version as opposed to the normal ones?

Thanks.

[Mao]

'Solve(expr=expr,var)' is an algebraic method.
'Int(expr,var,x0,x1)' is an algebraic method.
'd(expr,var,x0)' is an algebraic method.
'nSolve(expr=expr,var)' is a numerical method
'nInt(expr,var,x0,x1)' is a numerical method
'nDeriv(expr,var,x0)' is a numerical method

With complicated expressions, algebraic methods can often take a long time, since the algebra can get very very complex, or there is simply no elementary solutions (where algebra simply cannot solve it).
Luckily, questions with complicated expressions usually require a numerical answer. Numerical methods are a lot more processor-friendly compared to intensive algebra, since they use simple calculations, and no algebra.

With simple expressions, the algebraic methods are preferred as they give exact answers, not numerical approximations.

[Gloamglozer]

'Solve(expr=expr,var)' is an algebraic method.
'Int(expr,var,x0,x1)' is an algebraic method.
'd(expr,var,x0)' is an algebraic method.
'nSolve(expr=expr,var)' is a numerical method
'nInt(expr,var,x0,x1)' is a numerical method
'nDeriv(expr,var,x0)' is a numerical method

With complicated expressions, algebraic methods can often take a long time, since the algebra can get very very complex, or there is simply no elementary solutions (where algebra simply cannot solve it).
Luckily, questions with complicated expressions usually require a numerical answer. Numerical methods are a lot more processor-friendly compared to intensive algebra, since they use simple calculations, and no algebra.

With simple expressions, the algebraic methods are preferred as they give exact answers, not numerical approximations.

Mao, so you're saying that by using the "n", it can avoid the massive lag in CAS calculators?  Cos my TI-89 can get really annoying.

[Mao]

that is correct, but of course conditions apply, that is only true in some cases.