Sum, Difference, Product, Quotient, and Composition of Functions

The sum, difference, product, quotient, or composition of two given functions are easy to graph from the two given ones.

Go to the function edit window with GRAPH/y(x)= (see Graphing Functions). Enter the two given functions as y1 and y2. Unselect each of these by choosing the SELCT option of the y(x)= menu.

• To graph the sum of these two funtions enter for y3 the expression y1 + y2.
  
  
• To graph the difference of these two funtions enter for y3 the expression y1 - y2 or the expressiong y2 - y1 depending on the order you wish to subtract.
  
  
• To graph the product of these two funtions enter for y3 the expression y1 * y2.
  
  
• To graph the quotient of these two funtions enter for y3 the expression y1 / y2 or the expression y2 / y1 depending on the order you wish to divide.
  
  
• To graph the composite of these two funtions enter for y3 the expression y1(y2) or y2(y1) depending on the desired order.