∫ − 1 0 ln ( x + 1 ) x 2 + 2 x d x
The integral above has a simple closed form. Find this closed form.
Give your answer to 3 decimal places.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Well done. btw, congrats on 500 upvotes (im still on 476)
Log in to reply
Thanks!
Log in to reply
btw, how do you know when to use the "derivative method" to find an integral?
Log in to reply
@Anish Puthuraya – Sorry, I don't know that. But you can keep that as a way to be applied at last.
@Anish Puthuraya – This might help.
@jatin yadav can you share the link of the question here , i wrote but did'nt founded it , i too want to upvote it
Brilliant!
That is commendable!
that was easy with feymann calculus.! :)
you are a genius, man!!
Problem Loading...
Note Loading...
Set Loading...
Put x + 1 = t to get the integral as :
∫ 0 1 ln ( x ) x 2 − 1 d x
Let I ( a ) = ∫ 0 1 ln ( x ) x a − 1 d x
⇒ I ′ ( a ) = ∫ 0 1 ln ( x ) x a ln ( x ) d x = a + 1 1
⇒ I ( a ) = ln ( a + 1 ) + c
Also, I ( 0 ) = ∫ 0 1 ln ( x ) 1 − 1 d x = 0
Hence, I ( a ) = ln ( a + 1 )
Hence, our answer is ln ( 2 + 1 ) = ln ( 3 ) = 1 . 0 9 8 6 1