A quick fix
Add the original test case used by sushant
Return a `mul` when the denominator is one or minus_one in `div`
Move the check for `minus_one` from `div` to `pow`
Merge pull request #175 from thilinarmtb/div_bug

A quick fix for #174
Merge branch 'master' into inverse_trig

This commit fixes the tests failing for negative sign in denominator