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Evaluate the integral (((ln(x)^4)/x))

2007-04-16 15:19:59 · 3 answers · asked by garrett m 1 in Science & Mathematics Mathematics

3 answers

∫ ( [ln(x)]^4 / x dx )

To solve this we're going to use substitution. But first, I'll show you a preliminary step to help you see it in action.

Splitting the integral into a product, we get

∫ ( [ln(x)]^4 (1/x) dx )

Here's where we use substitution.
Let u = ln(x). Then
du = (1/x) dx

Note that (1/x) dx is the tail end of our integral; as a result, du will be the tail end after the substitution.

∫ (u^4 du )

Integrate using the reverse power rule.

(1/5)u^5 + C

But u = ln(x), so back-substituting, we get

(1/5)[ln(x)]^5 + C

2007-04-16 15:26:47 · answer #1 · answered by Puggy 7 · 0 0

Let u = ln x.
Then du = dx/x.
From here it is just integrating u^4 du, which I am sure you are up for.

2007-04-16 22:27:12 · answer #2 · answered by jiyuztex 2 · 0 0

integral (4lnx) / x

let ln x =u

1/x dx=du

integral 4udu

=2u^2
=2(lnx)^2 + C

2007-04-16 22:30:06 · answer #3 · answered by iyiogrenci 6 · 0 0

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