Can't get symbolic numbers.

I have been trying to get MATLAB to display an answer with symbolic numbers (i.e. fractions like 1/5, 3/8, simple stuff like that), but I cannot get it to work, and I don't know why. I will write sym(1/5) and it outputs 0.2. I have tried using sym(1/5, 'r') and the same thing happens. I have also tried many other things like format rational, rat(1./5), etc, and every time it still outputs 0.2. The 0.2 is symbollic, but I would just like to see it as a fraction. How do I fix this?

Answer 1

[Star Strider]

The sympref function should work, specifically:

sympref('FloatingPointOutput',false);

or:

sympref('FloatingPointOutput','default');

since the default is to use symbolic output.

Answer 2

[Paul]

Hi Austin,

Seems to work here as you expect.

sym(1/5)

ans = 

sym(1/5,'r')

ans = 

But the preceeding results are based on the default sympref

sympref

ans = struct with fields:
           FourierParameters: [1    -1]
           HeavisideAtOrigin: 1/2
            AbbreviateOutput: 1
               TypesetOutput: 1
         FloatingPointOutput: 0
      PolynomialDisplayStyle: 'default'
    MatrixWithSquareBrackets: 0

If you change this sympref

sympref('FloatingPointOutput',true);

Then we get

sym(1/5)

ans = 

0.2000

sym(1/5,'r')

ans = 

0.2000

Maybe you have the FloatingPointOutput = true in your sympref.