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    I am doing A2 Edexcel Maths, I am kind of confused on topic 4.5 (page 43) which involves setting up a differential equation from the information given in context. Can someone please explain to me what this topic is basically about and how you write the differential equations from the context. Much appreciated!
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    (Original post by Caped_Crusader96)
    I am doing A2 Edexcel Maths, I am kind of confused on topic 4.5 (page 43) which involves setting up a differential equation from the information given in context. Can someone please explain to me what this topic is basically about and how you write the differential equations from the context. Much appreciated!
    Best to post in the Maths forum:
    http://www.thestudentroom.co.uk/forumdisplay.php?f=38

    How much do you know already? Are there some questions you can do, and some questions you can't?

    If you are completely stuck I would suggest going to the start of 4.5 (or even Chapter 4, but I can't remember what's in that chapter and whether it helps with 4.5) and work through that. Perhaps you could use examsolutions or a similar resource as well to get someone to talk you through things.

    If you're stuck with a particular question, post it in the Maths forum
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    (Original post by Caped_Crusader96)
    I am doing A2 Edexcel Maths, I am kind of confused on topic 4.5 (page 43) which involves setting up a differential equation from the information given in context. Can someone please explain to me what this topic is basically about and how you write the differential equations from the context. Much appreciated!
    I'll move this to the maths section for you so you hopefully get the help you need

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    (Original post by Caped_Crusader96)
    I am doing A2 Edexcel Maths, I am kind of confused on topic 4.5 (page 43) which involves setting up a differential equation from the information given in context. Can someone please explain to me what this topic is basically about and how you write the differential equations from the context. Much appreciated!
    Why don't you try giving us an example so we can walk you through out and dissect it?
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    (Original post by Zacken)
    Why don't you try giving us an example so we can walk you through out and dissect it?
    Please, no biology!!
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    (Original post by B_9710)
    Please, no biology!!
    And here I was thinking B_9710 stood for Biology_9710.
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    (Original post by Zacken)
    And here I was thinking B_9710 stood for Biology_9710.
    :eek::eek::eek:
    NEVER!!!!!!
    How offensive.
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    Biology is the devil's science, will vote for whatever party campaigns to have it banned
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    (Original post by SeanFM)
    Best to post in the Maths forum:
    http://www.thestudentroom.co.uk/forumdisplay.php?f=38

    How much do you know already? Are there some questions you can do, and some questions you can't?

    If you are completely stuck I would suggest going to the start of 4.5 (or even Chapter 4, but I can't remember what's in that chapter and whether it helps with 4.5) and work through that. Perhaps you could use examsolutions or a similar resource as well to get someone to talk you through things.

    If you're stuck with a particular question, post it in the Maths forum
    (Original post by Zacken)
    Why don't you try giving us an example so we can walk you through out and dissect it?
    Here is a question, its question 8 on page 46 in C4 Edexcel textbook:

    A metal bar is heated to a certain temperature, then allowed to cool down and it is noted that, at time t, the rate loss of temperature is proportional to the difference in temperature between the metal bar, theta, and the temperature of its surroundings theta0. Write down a differential equation relating theta and t.

    so that means dtheta/dt = rate of change in temperature.

    I'm not sure what to do next.
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    (Original post by Caped_Crusader96)
    Here is a question, its question 8 on page 46 in C4 Edexcel textbook:

    A metal bar is heated to a certain temperature, then allowed to cool down and it is noted that, at time t, the rate loss of temperature is proportional to the difference in temperature between the metal bar, theta, and the temperature of its surroundings theta0. Write down a differential equation relating theta and t.

    so that means dtheta/dt = rate of change in temperature.

    I'm not sure what to do next.
    Okay, so you know from GCSE that if y is proportional to x then y = kx for some constant k, right?

    In this case - you know the rate loss of temperature (dtheta/dt) is proportion to the difference between the metal bar and the surroundings (theta - theta_0)

    So you can write: \displaystyle \frac{\mathrm{d}\theta}{\mathrm{  d}t} = -k(\theta - \theta_0)

    You okay with this?

    Note that I want k to be positive and \frac{d\theta}{dt} is the rate of increase, so if I want to turn that into a loss I'll need to factor in that - sign as I have above.
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    (Original post by drandy76)
    Biology is the devil's science, will vote for whatever party campaigns to have it banned
    Psychology??
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    (Original post by Student403)
    Psychology??
    Took that at GCSE, was basically like a sciencey geography, case study after case study
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    (Original post by drandy76)
    Took that at GCSE, was basically like a sciencey geography, case study after case study
    *shudders*
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    am I too late?
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    (Original post by Zacken)
    Okay, so you know from GCSE that if y is proportional to x then y = kx for some constant k, right?

    In this case - you know the rate loss of temperature (dtheta/dt) is proportion to the difference between the metal bar and the surroundings (theta - theta_0)

    So you can write: \displaystyle \frac{\mathrm{d}\theta}{\mathrm{  d}t} = -k(\theta - \theta_0)

    You okay with this?

    Note that I want k to be positive and \frac{d\theta}{dt} is the rate of increase, so if I want to turn that into a loss I'll need to factor in that - sign as I have above.
    You are a saviour man. Thank you so much! :adore:
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    (Original post by Caped_Crusader96)
    You are a saviour man. Thank you so much! :adore:
    Haha, glad that helps.
 
 
 
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