Input: tosum(exp(x))
Write: `tosum(exp(x))`
Output: $$ convert \ to \ sum :\\ \ exp(x) == \sum _{k=0}^\infty \frac {{x}^{k}}{(k)!} $$ Result:$$\sum _{k=0}^\infty \frac {{x}^{k}}{(k)!}$$