Press to access the numerical integration option which approximates the definite integral of an expression with respect to a variable from a start value to an end value.

Next, enter an expression, the variable, a start value, and an end value separated by commas. For example, to find the antiderivative of x

`tol`

is used to determine how accurate to calculate
the integral. The TI tries to keep the absolute error under `tol`

.
A smaller value yields a more accurate integral but takes longer to compute.
It can be changed in the tolerance editor available by pressing
,
typically about 0.001.For more specific information and tips see Integration on the TI-how does it work?.