Applicare la formula: $\int\frac{e^x}{x}dx$$=Ei\left(x\right)+C$, dove $int2.718281828459045^x/x$dx=\int\frac{e^{\left(\sqrt{x}\right)}}{\sqrt{x}}dx$, $2.718281828459045=e$, $int2.718281828459045^x/x=\int\frac{e^{\left(\sqrt{x}\right)}}{\sqrt{x}}$, $x=\sqrt{x}$, $2.718281828459045^x=e^{\left(\sqrt{x}\right)}$ e $2.718281828459045^x/x=\frac{e^{\left(\sqrt{x}\right)}}{\sqrt{x}}$

Applicare la formula: $\left[x\right]_{a}^{b}$$=eval\left(x,b\right)-eval\left(x,a\right)+C$, dove $a=4$, $b=9$ e $x=Ei\left(\sqrt{x}\right)$