Join TSR now and get all your revision questions answeredSign up now

C3 (Not MEI) - Thursday June 14 2012, AM Watch

    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    Right someone please help me out?

    \LARGE \int \frac{2}{x-3}


    How would I do it? :yep: I've tried looking at \LARGE \int \frac{f'(x)}{f(x)} but it doesn't really work... Pleaseeee help
    I thought it would be just 2ln(x-3)
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Sem193)
    I thought it would be just 2ln(x-3)
    Exactly what I thought, but apparently its not
    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    Exactly what I thought, but apparently its not
    That's weird. I guess I need help too.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Sem193)
    That's weird. I guess I need help too.
    I'll have a look at that tomorrow, calling it a day now!
    Tomorrows plan is to do some other subject for the morning and end the day with C3. Is it worth doing tons of questions on 'numerical methods'? - I mean, there's only two things to it and they never change. Only iteration & sign change.

    There is a lot of questions in the C3/C4 book but Idk, what dya think I should do?
    Offline

    2
    ReputationRep:
    hey everyone! can anyone help me on this question \int \frac{e^{2x}}{e^{2x}+3} dx any help would be much appreciated! thanks!
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by king0vdarkness)
    hey everyone! can anyone help me on this question \int \frac{e^{2x}}{e^{2x}+3} dx any help would be much appreciated! thanks!
    \LARGE \int \frac{e^2^x}{e^2^x+3} dx

    This has to be in the form: \huge \int \frac{f'(x)}{f(x)}dx= k ln\left |f(x) \right | + c


    So: \huge \frac{1}{2}\int \frac{2e^2^x}{e^2^x+3}= \frac{1}{2}ln(e^2^x+3)+c

    Let me know how that works out for ya
    • Thread Starter
    Offline

    2
    ReputationRep:
    Just finished going over Trigonometry in the book, dont' the first two pages of the misc questions. The last three questions -Too much effort Decided to just move on
    • Thread Starter
    Offline

    2
    ReputationRep:
    Having trouble with the equation shown, I know how to get the values of x but the problem is what way does the \huge > sign go?

    I sort of understand which way it is when working the equation out algebraically. I want to be able to know which way the sign is supposed to go directly from the graph of the function. Is it even possible?
    I can draw it on my calculator with no problem, but when writing the solution of x, how am I supposed to know which way the  > sign is supposed to be?
    \huge \left | x+2 \right |> 2x+1

    Thanks
    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    \LARGE \int \frac{e^2^x}{e^2^x+3} dx

    This has to be in the form: \huge \int \frac{f'(x)}{f(x)}dx= k ln\left |f(x) \right | + c


    So: \huge \frac{1}{2}\int \frac{2e^2^x}{e^2^x+3}= \frac{1}{2}ln(e^2^x+3)+c

    Let me know how that works out for ya
    Thanks a lot for your help... but i'm still a little confused on how you got your answer, i'm getting almost the same answer as you but it's with a 1/2e^3 ln(e^2^x+3)+c instead of 1/2 ln(e^2^x+3)+c. Could you go through all the steps of your working please thank you!
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by king0vdarkness)
    Thanks a lot for your help... but i'm still a little confused on how you got your answer, i'm getting almost the same answer as you but it's with a 1/2e^3 ln(e^2^x+3)+c instead of 1/2 ln(e^2^x+3)+c. Could you go through all the steps of your working please thank you!
    is my answer correct? I might be wrong too!

    Right the way I did It:

    -I looked at the equation. I differentiated the bottom to see if the differential is the same as the top. It's not.
    - So I worked out what I needed to add to the top to make it equal to the differential of the bottom.
    -I put a 2 at the top. HOWEVER you cant just put a number there...So to cancel that 2 out, I put 1/2 on the outside. This means, the equation is sill the same.

    then just put it in the form of ln(...)

    that's it !
    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    is my answer correct? I might be wrong too!

    Right the way I did It:

    -I looked at the equation. I differentiated the bottom to see if the differential is the same as the top. It's not.
    - So I worked out what I needed to add to the top to make it equal to the differential of the bottom.
    -I put a 2 at the top. HOWEVER you cant just put a number there...So to cancel that 2 out, I put 1/2 on the outside. This means, the equation is sill the same.

    then just put it in the form of ln(...)

    that's it !
    Yh you're right thank you so much! You're a great help! Good luck with all your future endeavors!
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by king0vdarkness)
    Yh you're right thank you so much! You're a great help! Good luck with all your future endeavors!
    If you do need any more help, please post it up here! It really does help me learn
    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    If you do need any more help, please post it up here! It really does help me learn
    Will do!!
    Offline

    2
    ReputationRep:
    (Original post by Doctor.)
    If you do need any more help, please post it up here! It really does help me learn
    Are you doing C4 too?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Sem193)
    Are you doing C4 too?
    (Original post by Sem193)
    Are you doing C4 too?
    I am, yeah there Is another thread somewhere for C4 too!
    Offline

    0
    ReputationRep:
    Bricking it for this exam, managed to just scrape a B overall for AS maths inc a U in stats really need a B overall!!! what are the grade boundaries like for a B? And I havent even started past papers yet... Gotta learn it all first
    Offline

    0
    ReputationRep:
    please may someone help with 8iii?
    really confused myself!
    thank you!
    http://pdf.ocr.org.uk/download/pp_10..._gce_4723.pdf?
    Offline

    0
    ReputationRep:
    How are you guys feeling ahead of this, then????
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by 710)
    How are you guys feeling ahead of this, then????
    Not all that good really I need to do more work on it tbh
    • Thread Starter
    Offline

    2
    ReputationRep:
    Hey folks, I'll be doing C3 tomorrow, got a whole stack of questions sorted.

    So ill post stuff in here if I need help!
 
 
 
Poll
How are you feeling about Results Day?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.