Input: harmonic(-3,1,x)
Write: `harmonic(-3,1,x)`
Output: $$ harmonic(-3,1,x) == \frac{1}{4}\ {x}^{2}+\frac{1}{2}\ {x}^{3}+\frac{1}{4}\ {x}^{4} $$ Result:$$\frac{1}{4}\ {x}^{2}+\frac{1}{2}\ {x}^{3}+\frac{1}{4}\ {x}^{4}$$