The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

C3 Integration Question

Can anyone integrate x+(4/x) and use this to work out the area in the bounds x=5 and x=2 for the line y=x+(4/x)?
I have been struggling on this all day so if anyone can help, that would be appreciated.
Original post by JennaK
Can anyone integrate x+(4/x) and use this to work out the area in the bounds x=5 and x=2 for the line y=x+(4/x)?
I have been struggling on this all day so if anyone can help, that would be appreciated.



Perhaps you could show some working as that is a very straightforward question
Reply 2
Avatar for TeeEm
TeeEm
19
how does this help?
Not a good idea, in my opinion
Reply 4
Avatar for TeeEm
TeeEm
19
Not to worry

I am the King blunderer here!

:biggrin:
Original post by JennaK
Can anyone integrate x+(4/x) and use this to work out the area in the bounds x=5 and x=2 for the line y=x+(4/x)?
I have been struggling on this all day so if anyone can help, that would be appreciated.


This is an integration by recognition question so you need to list the basic derivatives you have learned in C3 and try to match them up with 1/x and you integrate x as you did in C1/2.
Not worth quitting

We have already judged

:biggrin:
The power rule wouldn't work here..
:tongue: k
Reply 9
Avatar for JennaK
JennaK
OP
3
Original post by Dalek1099
This is an integration by recognition question so you need to list the basic derivatives you have learned in C3 and try to match them up with 1/x and you integrate x as you did in C1/2.


Rewriting it hasn't helped. I realise the answer that it must have something to do with the fact that 1/x= lnx but the main bit that is confusing me is the x at the front. It isn't cancelling out when I attempt this question, so I have no idea what to do.
Original post by JennaK
Rewriting it hasn't helped. I realise the answer that it must have something to do with the fact that 1/x= lnx but the main bit that is confusing me is the x at the front. It isn't cancelling out when I attempt this question, so I have no idea what to do.


Surely you know what you get when you integrate x
Original post by JennaK
Rewriting it hasn't helped. I realise the answer that it must have something to do with the fact that 1/x= lnx but the main bit that is confusing me is the x at the front. It isn't cancelling out when I attempt this question, so I have no idea what to do.


the 4/x integrates to 4lnx due to the fact the derivative of lnx is 1/x and to integrate x you use the rule you learnt in C1/C2 that x^n integrates to x^n+1/(n+1).
(edited 9 years ago)
Reply 12
Avatar for davros
davros
16
Original post by JennaK
Can anyone integrate x+(4/x) and use this to work out the area in the bounds x=5 and x=2 for the line y=x+(4/x)?
I have been struggling on this all day so if anyone can help, that would be appreciated.


Start with the basics.

What would you get if you integrated x + (4/x) without any limits?

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you