Simplify symbolic rational expressions

`expr`

can contain irrational subexpressions, such as`sin(x)`

and`x^(-1/3)`

.`simplifyFraction`

simplifies such expressions as if they were variables.`simplifyFraction`

does not apply algebraic identities.

You can also simplify rational expressions using the general simplification function `simplify`

. However, `simplifyFraction`

is more efficient for
simplifying rational expressions.