Question

${\int }_a^b\cos xdx$
Obtain the definite integral as a limit of d sum.

Answer 1

${\int }_a^b\cos xdx$

$\cos b-\cos a$

$\sum _{k=0}^{k=\infty }\frac{(-1{)}^k(b^{2k}-a^{2k})}{2k!}$