Input: d(d(sin(x),x,0.5),x,0.5)
Write: `d(d(sin(x),x,0.5),x,0.5)`
Output: $$ \frac{d^{{0.5}}\frac{d^{{0.5}}sin(x)}{dx^{{0.5}}}}{dx^{{0.5}}} == sin(0.5\ \pi +x) $$ Result:$$sin(0.5\ \pi +x)$$