# Knowledge Base

## Solution 13680: Finding Proper Fractions and Common Denominators on the TI-89, TI-89 Titanium, TI-92 Family or Voyage™ 200 Graphing Calculators.

### How do I find proper fractions and common denominators on the TI-89, TI-89 Titanium, TI-92 Family, or Voyage 200 graphing calculators?

The example below will demonstrate how to find proper fractions and common denominators of an expression on the TI-89, TI-89 Titanium, TI-92 family or Voyage 200.

Use the propFrac ([F2] 7) and comDenom ([F2] 6) functions. The syntax for the expressions is as follows:

propFrac (rational expression [,var]) - the variable is with respect to a proper fraction.

comDenom (expression [,var]) - the var is for common denominators that collect similar powers of this variable.

Example: Find the proper fraction for (x^4-2x^2+x)/(2x^2+x+4) then transform the answer into a ratio of a fully expanded numerator and a fully expanded denominator.

Solution:

(31x+60)/8 is the remainder of x^4-2x^2+x divided by 2x^2+x+4 and (x^2/2)-(x/4)-15/8 is the quotient.