Question

Integrate \[
\int 4e^{-x}\cos x \;dx
\]

Answer 1

I'll just keep it simple and do \[
\int e^{-x}\cos x\;dx
\]And multiply the \(4\) in later.

Answer 2

integrate by parts.

Answer 3

use ILATE rule.

Answer 4

\[
u=\cos x \quad dv=e^{-x}\;dx
\]