Use integration by parts to derive the following formula from the table of integrals.
∫x^n . ln |x|dx=x^n+1 [ln |x|/n+1]-1/(n+1)^2]+c, n≠-1.

Respuesta :

Answer:

[tex]ln|x|(\frac{x^{n+1}}{n+1})-\frac{x^{n+1}}{(n+1)^2}+C,n\neq -1[/tex]

Step-by-step explanation:

We have been given an indefinite integral [tex]\int \:x^n\:.\:ln\:|x|dx[/tex]. We are asked to integrate it.

We will use integration by pats to solve our given problem.

[tex]\int udvdx=uv-\int vdu[/tex]

Let [tex]u=ln|x|[/tex] and [tex]v'=x^n[/tex].

Now, we need to find du and v using above values.

[tex]\frac{du}{dx}=\frac{1}{x}[/tex]

[tex]du=\frac{1}{x}dx[/tex]    

[tex]v'=x^n[/tex]

[tex]v=\frac{x^{n+1}}{n+1}[/tex]

Substitute these values in integration by parts formula:

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\int \frac{x^{n+1}}{n+1}*\frac{1}{x}dx[/tex]

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\int \frac{x^{n+1}}{n+1}*x^{-1}dx[/tex]

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\frac{1}{n+1}\int x^{n+1-1}dx[/tex]

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\frac{1}{n+1}\int x^{n}dx[/tex]

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\frac{1}{n+1}*\frac{x^{n+1}}{n+1}+C[/tex]

[tex]\int \:x^n\:.\:ln\:|x|dx=ln|x|(\frac{x^{n+1}}{n+1})-\frac{x^{n+1}}{(n+1)^2}+C,n\neq -1[/tex]

Therefore, our required integral would be [tex]ln|x|(\frac{x^{n+1}}{n+1})-\frac{x^{n+1}}{(n+1)^2}+C,n\neq -1[/tex].