The Integral command is one of the most significant commands on the TI-Nspire CAS Calculus submenu. Press [MENU]→Calculus→Integral to open the Integral command. A template containing four fields is pasted to the entry line. The two leftmost fields are where you specify the lower and upper limits of integration. Leave these fields blank if you want to evaluate an indefinite integral.
Type the expression to be integrated in the field contained in the parentheses. The rightmost field is where you type the variable to integrate with respect to.
Review the first screen:
In the first line, the lower and upper limits of integration are omitted and the anti-derivative, less the constant of integration, is given.
In the second line, an expression is included for which the indefinite integral cannot be represented analytically. As a result, the coefficient, a, is written before the integral symbol, and the expression containing e is left in integral form.
The third line shows that, although the indefinite integral cannot be found for the same expression containing the number e, a corresponding definite integral can be evaluated.
Here are two comments about the second screen:
The first line shows that TI-Nspire provides an exact answer for a definite integral whenever possible.
The second line shows that you can force a decimal approximation by pressing [CTRL][ENTER].