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

    3
    ReputationRep:
    (Original post by Better)
    Can anyone recommend when I should finish the C4 Papers Please?

    Physics and Chemistry are taking up alot of time. I'm up to 2012 on the C3 Papers, my results thus far are pretty decent......

    Would Starting the real C4 papers on Thursday be leaving it too late?
    Have you done a good amount of practice for C4 yet, like Solomons and stuff? If so, starting the real C4 on Thursday should be fine, imo.
    Offline

    0
    ReputationRep:
    (Original post by AHarris)
    Attachment 224201

    Can anyone do part d of q15
    The answer in the back is wrong but I still have no idea how to get an answer :/


    Posted from TSR Mobile



    I rushed this but it's about finding limits for theta and multiplying the "y" expression by dx/d(theta) to integrate wrt theta I think
    Attached Images
     
    Offline

    1
    ReputationRep:
    For C3 trig questions (finding x)..
    When im at the stage where for example: cos(2x-36.87) = 2/5
    I normally write: let 2x-36.87 =b and then continue my working with cosb =2/5 as I find this easier.. Then convert it back later.

    When doing this I normally just find lots of values by adding and subtracting 360.. However can someone please tell me how to change the range so that I know when to stop e.g. if it was 0 < x < 180 what would it become when I let 2x-36.87 =b?

    Thanks
    Offline

    0
    ReputationRep:
    (Original post by bestfriends33)
    For C3 trig questions (finding x)..
    When im at the stage where for example: cos(2x-36.87) = 2/5
    I normally write: let 2x-36.87 =b and then continue my working with cosb =2/5 as I find this easier.. Then convert it back later.

    When doing this I normally just find lots of values by adding and subtracting 360.. However can someone please tell me how to change the range so that I know when to stop e.g. if it was 0 < x < 180 what would it become when I let 2x-36.87 =b?

    Thanks
    if 0 < x < 90 , -12 < B < 78 where B=x-12, you put the range boundaries in for x values.
    Offline

    1
    ReputationRep:
    (Original post by Tchombo)
    if 0 < x < 90 , -12 < B < 78 where B=x-12, you put the range boundaries in for x values.
    Thanks! So you just subs the range values into the equation..

    So for my question above would the range become -36.87 < x <323.13?
    • Study Helper
    Offline

    3
    ReputationRep:
    Someone give me some foul questions for C3, I need to prepare for the outcome that happening in M2!


    Posted from TSR Mobile
    Offline

    16
    ReputationRep:
    (Original post by MathsNerd1)
    Someone give me some foul questions for C3, I need to prepare for the outcome that happening in M2!


    Posted from TSR Mobile
    It's probably not that difficult, but it's the best I could come up with .

    Find \dfrac{d}{dx}(x^{e^x}). You are only allowed to use C3 methods though.
    Offline

    0
    ReputationRep:
    (Original post by Tchombo)
    I rushed this but it's about finding limits for theta and multiplying the "y" expression by dx/d(theta) to integrate wrt theta I think
    Did you forget to take it away from 5 at the end or am I missing something?
    • Study Helper
    Offline

    3
    ReputationRep:
    (Original post by brittanna)
    It's probably not that difficult, but it's the best I could come up with .

    Find \dfrac{d}{dx}(x^{e^x}). You are only allowed to use C3 methods though.
    I'll try this now and post my answer for you to check? I'm sure I can already see the method though


    Posted from TSR Mobile
    • Study Helper
    Offline

    3
    ReputationRep:
    (Original post by brittanna)
    It's probably not that difficult, but it's the best I could come up with .

    Find \dfrac{d}{dx}(x^{e^x}). You are only allowed to use C3 methods though.
    This just looks completely wrong, but who knows.

    Is this correct?

    Name:  ImageUploadedByStudent Room1370601946.900670.jpg
Views: 102
Size:  124.4 KB

    Edit: This is rubbish.
    Posted from TSR Mobile
    • Study Helper
    Offline

    3
    ReputationRep:
    (Original post by brittanna)
    It's probably not that difficult, but it's the best I could come up with .

    Find \dfrac{d}{dx}(x^{e^x}). You are only allowed to use C3 methods though.
    Ignore the last post, that's complete and utter rubbish, would this be it?

    Name:  ImageUploadedByStudent Room1370602220.146727.jpg
Views: 112
Size:  128.3 KB


    Posted from TSR Mobile
    Offline

    16
    ReputationRep:
    (Original post by MathsNerd1)
    Ignore the last post, that's complete and utter rubbish, would this be it?

    Name:  ImageUploadedByStudent Room1370602220.146727.jpg
Views: 112
Size:  128.3 KB


    Posted from TSR Mobile
    It looks similar to my answer, but I think your final answer is wrong.

    I got
    Spoiler:
    Show
    x^{e^x}(\frac{e^x}{x}+e^xlnx)
    • Study Helper
    Offline

    3
    ReputationRep:
    (Original post by brittanna)
    It looks similar to my answer, but I think your final answer is wrong.

    I got
    Spoiler:
    Show
    x^{e^x}(\frac{e^x}{x}+e^xlnx)
    Oh I had my base value wrong :-/ silly me -.-


    Posted from TSR Mobile
    Offline

    16
    ReputationRep:
    (Original post by MathsNerd1)
    Oh I had my base value wrong :-/ silly me -.-


    Posted from TSR Mobile
    .
    Offline

    0
    ReputationRep:
    (Original post by brittanna)
    It looks similar to my answer, but I think your final answer is wrong.

    I got
    Spoiler:
    Show
    x^{e^x}(\frac{e^x}{x}+e^xlnx)
    What was your method to get this?


    Posted from TSR Mobile
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by justinawe)
    Have you done a good amount of practice for C4 yet, like Solomons and stuff? If so, starting the real C4 on Thursday should be fine, imo.
    Yes mate I've finished all the Solomon for C4. Ah kk. Thanks for your input as always Justin!

    Just a bit nervous whether I can finish them fine.
    Offline

    3
    ReputationRep:
    (Original post by brittanna)
    It's probably not that difficult, but it's the best I could come up with .

    Find \dfrac{d}{dx}(x^{e^x}). You are only allowed to use C3 methods though.
    Is this C3???!

    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by AHarris)
    What was your method to get this?


    Posted from TSR Mobile
    You use implicit differentiation by taking logs on both sides.

    y= x^(e^x)

    lny= lnx^(e^x)

    lny= e^x lnx

    Differentiate
    Use the product rule on the RHS

    1/y(dy/dx)= e^xlnx + (e^x)/x

    Multiply both sides by y

    dy/dx = y( e^xlnx + (e^x)/x )

    replace y with x^(e^x)


    I am so sorry, but I cant do the whole fancy print screens they do. Someone else can do it for you
    Offline

    3
    ReputationRep:
    (Original post by StUdEnTIGCSE)
    Is this C3???!

    Posted from TSR Mobile
    yes. :cool:
    Offline

    3
    ReputationRep:
    (Original post by frogs r everywhere)
    yes. :cool:
    Ah k.
    I should go through the textbook, seem to have forgotten all the important stuff

    Posted from TSR Mobile
 
 
 
Poll
Which web browser do you use?

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.