Integrate (ln(x))^2 - Steps and Solution

In summary, the integration of (lnx)^2 involves using the integration by parts formula, setting u=(lnx)^2 and dv=dx. Simplifying the resulting equation, we get x(lnx)^2 - 2∫lnx dx. To integrate lnx, we use integration by parts again, setting u=lnx and dv=dx. This leads to the final solution of xln(x) - x.
  • #1
Rasine
208
0
intergrate (ln(x))^2

so i set u=(lnx)^2...which makes du=2lnx(1/x)

then i set dv=dx...which makes v=x

according to the formula for integration by parts i have

x(lnx)^2- integral x(2lnx)(1/x)
simplifying it i get x(ln)^2-2intergral lnx


and here is where i am stuck...what i the integral of lnx?
 
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  • #2
The derivative of (lnx)^2=(2lnx)/x.

[edit: of course that's you've written... i glanced and say ln(1/x)... sorry :blushing: ]

A hint for integrating lnx; use parts, taking dv=dx and u=lnx
 
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  • #3
How about integration-by-parts once again? :)
 
  • #4
xln(x) - x looks good from where I'm standing.

I just wondered "what function gives ln(x) when differentiated? Well ln(x)' = 1/x. So what if I try xln(x)? Now I get ln(x) + 1. So I need to add something to the mix that gives -1 when differentiated." Hence xln(x) - x.
 
  • #5
ohhh yes...do integration by part again...

thank you!
 

FAQ: Integrate (ln(x))^2 - Steps and Solution

What is the purpose of integrating (ln(x))^2?

The purpose of integrating (ln(x))^2 is to find the antiderivative or the inverse operation of differentiation. This will help us find the original function from its derivative.

What are the steps to integrate (ln(x))^2?

The steps to integrate (ln(x))^2 are:

  1. Use the power rule to rewrite (ln(x))^2 as (ln(x))^2 = ln(x) * ln(x)
  2. Use the product rule to split the product into two separate integrals:∫(ln(x))^2 dx = ∫ln(x) * ln(x) dx = ∫ln(x) dx * ∫ln(x) dx
  3. Integrate each individual integral using the power rule:∫ln(x) dx = x * ln(x) - x + C
  4. Combine the two integrals back together:∫(ln(x))^2 dx = (x * ln(x) - x + C) * (x * ln(x) - x + C) = (x * ln(x))^2 - 2x * ln(x) + x^2 + C

What is the solution to the integral of (ln(x))^2?

The solution to the integral of (ln(x))^2 is (x * ln(x))^2 - 2x * ln(x) + x^2 + C.

Can (ln(x))^2 be integrated using other methods?

Yes, (ln(x))^2 can also be integrated using substitution, where u = ln(x) and du = 1/x dx.

What are some applications of integrating (ln(x))^2?

Integrating (ln(x))^2 can be used in various mathematical and scientific fields such as economics, physics, and engineering. It can also be used in solving differential equations and finding the area under certain curves.

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