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${\displaystyle f(x)=f(x_{0})+{\frac {f'(x_{0})(x-x_{0})}{1!}}+{\frac {f''(x_{0})(x-x_{0})^{2}}{2!}}+{\frac {f'''(x_{0})(x-x_{0})^{3}}{3!}}+...}$

${\displaystyle f(x)=\sum _{n=0}^{\infty }{\frac {f^{(n)}(x_{0})}{n!}}(x-x_{0})^{n}}$

${\displaystyle f(x)\sim P(x)=f(a)+{\frac {f'(a)}{1!}}(x-a)+{\frac {f''(a)}{2!}}(x-a)^{2}+{\frac {f^{(3)}(a)}{3!}}(x-a)^{3}+\cdots .}$

${\displaystyle f(x)\sim P(x)=\sum _{n=0}^{\infty }{\frac {f^{(n)}(a)}{n!}}\,(x-a)^{n}}$

${\displaystyle \sin(x)=x-{\frac {x^{3}}{3!}}+{\frac {x^{5}}{5!}}-\cdots {\text{ for all }}x\!}$

${\displaystyle \sin(x)\sim x-{\frac {x^{3}}{3!}}}$

${\displaystyle f(x)=e^{2x}}$

${\displaystyle e^{2x}={\frac {(1)}{(e^{2})}}+{\frac {(2)(x+1)}{(1!)(e^{2})}}+{\frac {(2^{2})(x+1)^{2}}{(2!)(e^{2})}}+{\frac {(2^{3})(x+1)^{3}}{(3!)(e^{2})}}+...}$

${\displaystyle e^{2x}=\sum _{n=0}^{\infty }{\frac {(2)^{(n)}}{((n)!e^{2})}}(x+1)^{n}}$

${\displaystyle e^{x}=\sum _{n=0}^{\infty }{\frac {x^{n}}{n!}}=1+x+{\frac {x^{2}}{2!}}+{\frac {x^{3}}{3!}}+\cdots {\text{ for all }}x\!}$

${\displaystyle \ln(1-x)=-\sum _{n=1}^{\infty }{\frac {x^{n}}{n}}{\text{ for }}-1\leq x<1}$

${\displaystyle \ln(1+x)=\sum _{n=1}^{\infty }(-1)^{n+1}{\frac {x^{n}}{n}}{\text{ for }}-1<x\leq 1}$

${\displaystyle {\frac {1-x^{m+1}}{1-x}}=\sum _{n=0}^{m}x^{n}\quad {\mbox{ for }}x\not =1{\text{ and }}m\in \mathbb {N} _{0}\!}$

${\displaystyle {\frac {1}{1-x}}=\sum _{n=0}^{\infty }x^{n}{\text{ for }}|x|<1\!}$

${\displaystyle {\frac {1}{1-x}}=\sum _{n=0}^{\infty }x^{-n}{\text{ for }}|x|>1\!}$

${\displaystyle {\frac {x^{m}}{1-x}}=\sum _{n=m}^{\infty }x^{n}\quad {\mbox{ for }}|x|<1{\text{ and }}m\in \mathbb {N} _{0}\!}$

${\displaystyle {\frac {x}{(1-x)^{2}}}=\sum _{n=1}^{\infty }nx^{n}\quad {\text{ for }}|x|<1\!}$

${\displaystyle {\frac {1}{(1-x)^{2}}}=\sum _{n=1}^{\infty }nx^{n-1}\quad {\text{ for }}|x|>1\!}$

${\displaystyle {\sqrt {1+x}}=\sum _{n=0}^{\infty }{\frac {(-1)^{n}(2n)!}{(1-2n)(n!)^{2}(4^{n})}}x^{n}=1+\textstyle {\frac {1}{2}}x-{\frac {1}{8}}x^{2}+{\frac {1}{16}}x^{3}-{\frac {5}{128}}x^{4}+\dots {\text{ for }}|x|\leq 1}$

${\displaystyle (1+x)^{\alpha }=\sum _{n=0}^{\infty }{\alpha \choose n}x^{n}\quad {\mbox{ for all }}|x|<1{\text{ and all complex }}\alpha \!}$

${\displaystyle \sin x=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{(2n+1)!}}x^{2n+1}=x-{\frac {x^{3}}{3!}}+{\frac {x^{5}}{5!}}-\cdots {\text{ for all }}x\!}$

${\displaystyle \cos x=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{(2n)!}}x^{2n}=1-{\frac {x^{2}}{2!}}+{\frac {x^{4}}{4!}}-\cdots {\text{ for all }}x\!}$

${\displaystyle \tan x=\sum _{n=1}^{\infty }{\frac {B_{2n}(-4)^{n}(1-4^{n})}{(2n)!}}x^{2n-1}=x+{\frac {x^{3}}{3}}+{\frac {2x^{5}}{15}}+\cdots {\text{ for }}|x|<{\frac {\pi }{2}}\!}$

${\displaystyle \sec x=\sum _{n=0}^{\infty }{\frac {(-1)^{n}E_{2n}}{(2n)!}}x^{2n}{\text{ for }}|x|<{\frac {\pi }{2}}\!}$

${\displaystyle \arcsin x=\sum _{n=0}^{\infty }{\frac {(2n)!}{4^{n}(n!)^{2}(2n+1)}}x^{2n+1}{\text{ for }}|x|\leq 1\!}$

${\displaystyle \arccos x={\pi \over 2}-\arcsin x={\pi \over 2}-\sum _{n=0}^{\infty }{\frac {(2n)!}{4^{n}(n!)^{2}(2n+1)}}x^{2n+1}{\text{ for }}|x|\leq 1\!}$

${\displaystyle \arctan x=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{2n+1}}x^{2n+1}{\text{ for }}|x|\leq 1\!}$

${\displaystyle \sinh x=\sum _{n=0}^{\infty }{\frac {x^{2n+1}}{(2n+1)!}}=x+{\frac {x^{3}}{3!}}+{\frac {x^{5}}{5!}}+\cdots {\text{ for all }}x\!}$

${\displaystyle \cosh x=\sum _{n=0}^{\infty }{\frac {x^{2n}}{(2n)!}}=1+{\frac {x^{2}}{2!}}+{\frac {x^{4}}{4!}}+\cdots {\text{ for all }}x\!}$

${\displaystyle \tanh x=\sum _{n=1}^{\infty }{\frac {B_{2n}4^{n}(4^{n}-1)}{(2n)!}}x^{2n-1}=x-{\frac {1}{3}}x^{3}+{\frac {2}{15}}x^{5}-{\frac {17}{315}}x^{7}+\cdots {\text{ for }}|x|<{\frac {\pi }{2}}\!}$

${\displaystyle \mathrm {arsinh} (x)=\sum _{n=0}^{\infty }{\frac {(-1)^{n}(2n)!}{4^{n}(n!)^{2}(2n+1)}}x^{2n+1}{\text{ for }}|x|\leq 1\!}$

${\displaystyle \mathrm {artanh} (x)=\sum _{n=0}^{\infty }{\frac {x^{2n+1}}{2n+1}}{\text{ for }}|x|<1\!}$