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I_{n}=\int \left ( log\, x \right )^{n}dx, then I_{n}+nI_{n-1} =

Option: 1

n\left ( log\: X \right )^{n}
 


Option: 2

\left (n\: log\: X \right )^{n-1}


Option: 3

\left (log\: X \right )^{n-1}

 


Option: 4

\left (n\, log\: X \right )^{n}


Answers (1)

 

Integration By PARTS -

Let u and v are two functions then 

\int u\cdot vdx=u\int vdx-\int \left ( \frac{du}{dx}\int vdx \right )dx

- wherein

Where u is the Ist function v is he IInd function

 

 

Rule for integration by parts -

Take Ist function (u) as according I L A T E

 

- wherein

Where ,

I : Inverse

L : Logarithmic

A : Algebraic 

T : Trignometric

E : Exponential

 

 

I_{n}=\int (log\: x)^{n}dx

\therefore I_{n-1}=\int (log\: x)^{n-1}dx

Now I_{n}=\int (log\: x)^{n}1.dx

              = (log\: x)^{n}.x-n\int (log\: x)^{n-1}.\frac{1}{x}.x\; dx

I_{n}=n(log\: x)^{n}-n\: I_{n-1}

I_{n}+n\: I_{n-1}=n(log\: x)^{n}

Posted by

Ramraj Saini

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