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    (Original post by StUdEnTIGCSE)
    Ah k.
    I should go through the textbook, seem to have forgotten all the important stuff

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    Worry not! You will be more than fine. TSR users always are!!
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    Implicit differentiation is C4 syllabus? needless to say the method of implicit differentiation is pretty obvious and could come up in C3
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    (Original post by ChelseaSam)
    Implicit differentiation is C4 syllabus? needless to say the method of implicit differentiation is pretty obvious and could come up in C3
    But what for those who haven't done C4 still, it'll be unfair!

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    (Original post by StUdEnTIGCSE)
    Is this C3???!

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    You can do it using C3 knowledge (i.e. without using implicit differentiation).
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    (Original post by StUdEnTIGCSE)
    Is this C3???!

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    If you want to do it using C3 knowledge, then you would do it like this:

    Spoiler:
    Show
    y=x^{e^x}

    lny=e^xlnx

    y=e^{e^xlnx}

    \frac{dy}{dx}=(\frac{e^x}{x}+e^x  lnx)e^{e^xlnx}

    \frac{dy}{dx}=x^{e^x}(\frac{e^x}  {x}+e^xlnx)
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    (Original post by ChelseaSam)
    Implicit differentiation is C4 syllabus? needless to say the method of implicit differentiation is pretty obvious and could come up in C3

    (Original post by brittanna)
    If you want to do it using C3 knowledge, then you would do it like this:

    Spoiler:
    Show
    y=x^{e^x}

    lny=e^xlnx

    y=e^{e^xlnx}

    \frac{dy}{dx}=(\frac{e^x}{x}+e^x  lnx)e^{e^xlnx}

    \frac{dy}{dx}=x^{e^x}(\frac{e^x}  {x}+e^xlnx)
    Oh dear, didn't even realise implicit differentiation was C4!!! Never mind.
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    (Original post by brittanna)
    If you want to do it using C3 knowledge, then you would do it like this:

    Spoiler:
    Show
    y=x^{e^x}

    lny=e^xlnx

    y=e^{e^xlnx}

    \frac{dy}{dx}=(\frac{e^x}{x}+e^x  lnx)e^{e^xlnx}

    \frac{dy}{dx}=x^{e^x}(\frac{e^x}  {x}+e^xlnx)
    I don't understand how you went from line 1 to line 2. Other than that no problem

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    (Original post by StUdEnTIGCSE)
    I don't understand how you went from line 1 to line 2. Other than that no problem

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    Spoiler:
    Show
    y=x^{e^x}
    lny=lnx^{e^x}. Using the rule that lnb^a=alnb
    lny=e^xlnx


    Does this help?
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    (Original post by brittanna)
    Spoiler:
    Show
    y=x^{e^x}
    lny=lnx^{e^x}. Using the rule that lnb^a=alnb
    lny=e^xlnx


    Does this help?
    Ah yes, I forgot that ln was a logarithm function and that you can play with it like a logarithm.

    Thanks...

    Should be more careful next time...

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    http://www.youtube.com/watch?feature...v=P3owr0cwZbw#!

    do we need to know how to do this?
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    (Original post by zbert)
    http://www.youtube.com/watch?feature...v=P3owr0cwZbw#!

    do we need to know how to do this?
    Yeah, they asked it in one of the 2007 C3 papers.
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    june 2005 paper, Q8, core 4. Please can someone help? Cant get my head around this whole question! The mark scheme is just confusing me. Thankyou x
    Attached Images
      
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    (Original post by maleeha1)
    june 2005 paper, Q8, core 4. Please can someone help? Cant get my head around this whole question! The mark scheme is just confusing me. Thankyou x
    Can you upload the mark scheme for me to check my answer.
    Do you know how to prove the first question? Its pretty self-explanatory to be honest. But do ask!
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    (Original post by frogs r everywhere)
    Can you upload the mark scheme for me to check my answer.
    Do you know how to prove the first question? Its pretty self-explanatory to be honest. But do ask!
    with A, i understand how to explain the dv/dt bit, so id get the first mark. unsure of the second part about K.

    but yeah, attached the mark scheme. thanks :-)
    Attached Files
  1. File Type: doc C4_June_2005_mark_scheme (2).doc (453.5 KB, 33 views)
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    (Original post by frogs r everywhere)
    Oh dear, didn't even realise implicit differentiation was C4!!! Never mind.
    Implicit differentiation is C4? Really?
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    guys, could you please check the MS for C4 solomon paper E
    http://www.school-portal.co.uk/Group...urceId=3992050
    QUESTION 3)b) shouldn't it be +160
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    so nobody now is willing to help???
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    (Original post by YAH)
    guys, could you please check the MS for C4 solomon paper E
    http://www.school-portal.co.uk/Group...urceId=3992050
    QUESTION 3)b) shouldn't it be +160
    Yeah I think that what you've said is correct and they made an error.


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    (Original post by YAH)
    guys, could you please check the MS for C4 solomon paper E
    http://www.school-portal.co.uk/Group...urceId=3992050
    QUESTION 3)b) shouldn't it be +160
    If the previous line is correct, then yes, it should be +160.
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    Thanks
 
 
 
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