Question

∫(e^3x)/(1+e^3x)^8

Answer 1

Use u-substitution, where \(\large u = e^{3x}\)

Answer 2

Should I move the denominator up top and turn the ^8 to ^-8?

Answer 3

You could do that if it helps you see what to do bette :)

Answer 4

You'll have something like \(\large u^{-8}\)

Answer 5

sorry, use u-sub: \(\large u = e^{3x}\)

Answer 6

sorry, use u-sub: \(\large u =1+ e^{3x}\)

Answer 7

So my dx would be 3xe^4x?
What's the derivative of 1+e^3x?

Answer 8

\(\large du = 3e^{3x}\)

Answer 9

\(\huge \frac{du}{3}\)

Answer 10

That's not quite right, @cdbashir

Answer 11

just making easier what abbot said :
u = 1 + e^3x --------> e^3x = u - 1
du = 3 e^3x dx
1/3 du = e^3x dx

see ur integral becomes