Try it and see what happens. Enter the function f(x) = xex.

Keys:Display:

X 

X





 



 

Description:

Select equation mode. Enter the equation.

End of the equation. Checksum and length.

Cancels Equation mode.

Set the display format to SCI 3, specify the lower and upper limits of integration as zero and 10499, than start the integration.

Keys:

Display:

Description:

￿8(2)

 

Specifies accuracy level

 

and limits of integration.

 _

 



 

 



Selects Equation mode;

 

 

displays the equation.

X



Approximation of the

 

integral.



The answer returned by the calculator is clearly incorrect, since the actual integral of f(x) = xexfrom zero to is exactly 1. But the problem is not that was represented by 10499, since the actual integral of this function from zero to 10499 is very close to 1. The reason for the incorrect answer becomes apparent from the graph of f(x) over the interval of integration.

E-4More about Integration