I'm stuck finding the antiderivative to solve an integral. It's step 6 underlined with a "?".
I think it should be - ( 1/5 * e^5x * cos9x), then we add the C.
Isn't d/dx of e^5x = e^4x * 5 ?
Also, I list it as simply du = e^5x dx because my teacher does that for some reason. For instance in the example of e^x he lists it as e^x = e^x dx. So I did the same.. I don't want to learn something the wrong way here I thought my way of showing it was correct.
So if I were to fix this would the rest be ok?