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# differentiating lnx

1. would differentiating xlnx give 1/x?

the lnx part gives 1/x and the x 1 so is that correct?

thanks
2. No, it's incorrect. Are you familiar with the product rule?
3. Product rule: x(lnx)' + x'(lnx)=1+lnx

So, what you said in yuor first line is wrong, but the second line is kind of correct...
4. no.

product rule

differentiating a product uv = v(du/dx) + u(dv/dx)

u = x

v = lnx

therefore differentiating xlnx = lnx(1) + x(1/x) = lnx + 1
5. No it won't.

Using product rule, it becomes [ x * 1/x ] + [ 1/x ] or in other words, 1/x + 1.

Edit: Holy ****, this forum is full of mathematical hawks.

OP torn to pieces
6. (Original post by sdt)
No it won't.

Using product rule, it becomes [ x * 1/x ] + [ 1/x ] or in other words, 1/x + 1.

Edit: Holy ****, this forum is full of mathematical hawks.

OP torn to pieces
don't you mean lnx? ^^

(post farming ftw)
7. thanks all
8. (Original post by amjw)
don't you mean lnx? ^^

(post farming ftw)

Doh! Yes indeed. I went over this about 30 times trying to differentiate x^x. Maybe I'm mathematically challenged

Not post farming, I didn't even realise what I wrote.
9. (Original post by sdt)
Doh! Yes indeed. I went over this about 30 times trying to differentiate x^x. Maybe I'm mathematically challenged

Not post farming, I didn't even realise what I wrote.
i meant me
10. :]
11. ... over 2 year bump.
12. Doh! Yes indeed. I went over this about 30 times trying to differentiate x^x. Maybe I'm mathematically challenged
To differentiate x^x write it as:

And differentiate using the product and chain rule.
13. (Original post by anshul95)
To differentiate x^x write it as:

And differentiate using the product and chain rule.
or he can use the logarithmic differentiation

differenciating both sides

14. @ztibor yes you could do that but I didn't know whether or not the person knew implicit
15. you should use Chain rule

16. (Original post by safety280)
you should use Chain rule

You waited 6 months after the almost-three-years-old thread had died to post something which isn't even correct (or is too vague to be used in any sensible way)...

Oh, and welcome to TSR.
17. (Original post by Farhan.Hanif93)
You waited 6 months after the almost-three-years-old thread had died to post something which isn't even correct (or is too vague to be used in any sensible way)...

Oh, and welcome to TSR.

hey, first, I was googling that function then I got a link for this thread , chain rule in this case is perfectly applied and sensible.

thanks
18. (Original post by safety280)

hey, first, I was googling that function then I got a link for this thread , chain rule in this case is perfectly applied and sensible.

thanks
product rule actually.
19. (Original post by anshul95)
product rule actually.
yeah it's actually tomato tometo things

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