Continuidad de una funcion
\ La \ funcion \ es \ continua \ para \ x=a, \ si \ se \ cumple \ \\ \phantom{1} \\
lim_{x \to a} f(x)=f(a)Sumas de Riemman
\displaystyle\sum_{i=1}^n C=Cn \\ \phantom{1} \\\displaystyle\sum_{i=1}^n i=\frac {n(n+1)}{2} \\ \phantom{1} \\ \displaystyle\sum_{i=1}^n i^2=\frac {n(n+1)(2n+1)}{6} \\ \phantom{1} \\ \displaystyle\sum_{i=1}^n i^3=\frac {n^2(n+1)^2}{4} \\ \phantom{1} \\ \displaystyle\sum_{i=1}^n i^4=\frac {n(n+1)(6n^3+9n^2+n-1)}{30} \\ \phantom{1} \\ \displaystyle\sum_{i=1}^n \frac {1}{i(i+1)}=\frac {n}{(n+1)} \\ \phantom{1} \\ \displaystyle\sum_{i=1}^n i^5=\frac {n^2(n+1)^2(2n^2+2n-1)}{12}