\displaystyle f(x)=f(a)+(x-a)\frac{f^{\prime}(a)}{1!}+(x-a)^{2}\frac{f^{\prime\prime}(a)}{2!}+\cdots+(x-a)^{n-1}\frac{f^{(n-1)}(a)}{(n-1)!}+(x-a)^{n}\frac{f^{(n)}(\xi)}{n!}