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integrate ln x

can someone tel me why this isnt correct

according to this site, the answer should be xlnx

thanks

I thought if you id it by parts you got xlnx - x
My maths teacher told me to learn it so I havent actually worked it out cause i cant be bothered.

Reply 2

mikesgt2

manps

can someone tel me why this isnt correct

according to this site, the answer should be xlnx

thanks

No, the site is correct. Type in "Log[x]" into the box and it will give the answer you are looking for.

Reply 3

S@sha

manps

can someone tel me why this isnt correct

according to this site, the answer should be xlnx

thanks

that's the right answer in the pdf. (didn't check the working though, but it's likely to be right, isn't it?)

Reply 4

Juwel

Was anyone else completely relaxed despite the prospect of P2 a day away? I have P2 on Wednesday yet I don't feel nervous. I'm actually more worried that I'm too relaxed...

Reply 5

Nylex

Yannis

that's the right answer in the pdf. (didn't check the working though, but it's likely to be right, isn't it?)

The working is right.

Reply 6

friday13th

Example
Find ò ln x dx

To integrate this, we use a trick, rewrite the integrand (the expression we are integrating) as 1.lnx . We then let v = ln x and du/dx = 1 .

Hence ò ln x dx = x ln x - ò x (1/x) dx

= x lnx - ò 1dx

= x lnx – x + constant

the site here had swapped the Vs and Us in the formula, damn them- use the exam book version