Question

Solve:
${\int }_{-1}^1{e}^{x}dx$.

Answer 1

$I={\int }_{-1}^1{e}^{x}dx=e^x{|}_{-1}^1=e^1-e^{-1}=e-\frac{1}{e}$
$[\because {\int }_a^{b}f(x)dx=I(x){|}_a^b=I(b)-I(a\left)\right]$.