this is a L-R Series Circuit with

V= 240 cos 10t

R= 100 Ohm

L= 20 Henry

It asks to find current in circuit at any time if initially there is no current.

this is from my lecture notes so there is a step im not sure how to get.

d/dt(ie^5t) = 12 e^5t cos 10t

ie^5t = 12 ∫e^5t cos 10t dt

= 12/25 e^5t [cos 10t + 2sin 10t] +c

how do i integrate e^5t cos 10t to get to the next step?