Function Integration

Suppose we want to use the calculator to compute the intergral

Press and enter the function into Y₁.

Make sure the function is turned on.

Method 1: Using the command fnInt

The syntax for this command is: fnInt(function,X,a,b) where a is the starting value and b is the ending value of the integral.

From the home screen do the following.

• Press
• Choose 9:fnInt.
• Now enter the variable name that corresponds to where the formula was entered, for example Y₁
  • Note: You may choose to just type the function at this point.
• Press
• Type the starting value. For this example press
• Press
• Type the ending value. For this example press
• Press
• Press

Using the example from above should now display the following.

If needed you can convert the answer to a fraction.

Method 2: Using a Graphing Screen

• Press and enter the function into Y₁.
• Set thewindow. Be sure that the starting and ending value for the integral is between the X-min and X-max values. For this problem I used
  X-min = -10, X-max = 10, Y-min = -10, and Y-Max = 100
  
  • Note: The y-scale is not important. The Zoom Fit option may be used for these values.

• Press
• Press
• Choose 7:f(x)dx.
• You will now see the words LowerLimit?. Enter the starting value for the integral. For the above example this is 1. The calculator should now display the following.

• Press

• You will now see the words UpperLimit?. Enter the ending value for the integral. For the above example this is 5. The calculator should now display the following.

• Press

The calculator should now display the following.

It is not possible to convert the answer from this method to a fraction.