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    Are you allowed to do multiple attempts at a question and if one of them is correct get full marks? Of course only if the number of possible answers is infinite.
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    (Original post by TheFarmerLad)
    Hate proof by induction
    It's funny because a lot of people say that but if you're doing STEP then it's one of the most valuable tools for proof. I guess it's just getting used to how the exam board want it set out.
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    (Original post by Nikhilm)
    You can't do that for a dy/dx expansion though right?
    Why not?
    Spoiler:
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    Expansion of y=cosx

    \dfrac{dy}{dx} = -sinx

    \dfrac{d^{2}y}{dx^{2}} = -cosx

    f(x) = f(0) + xf'(0) + \dfrac{x^{2}f''(0)}{2!}

     f(x) = cosx = 1 - \dfrac{x^{2}}{2!}

    Let  x = 0.1

    f(0.1) = cos0.1 \approx 1-\dfrac{(0.1)^{2}}{2!}

     cos0.1 = 0.99500416

     1-\dfrac{(0.1)^{2}}{2!} = 0.995
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    (Original post by edothero)
    Why not?
    Spoiler:
    Show
    Expansion of y=cosx

    \dfrac{dy}{dx} = -sinx

    \dfrac{d^{2}y}{dx^{2}} = -cosx

    f(x) = f(0) + xf'(0) + \dfrac{x^{2}f''(0)}{2!}

     f(x) = cosx = 1 - \dfrac{x^{2}}{2!}

    Let  x = 0.1

    f(0.1) = cos0.1 \approx 1-\dfrac{(0.1)^{2}}{2!}

     cos0.1 = 0.99500416

     1-\dfrac{(0.1)^{2}}{2!} = 0.995
    No, i mean when the question is given in as a differential equation, not in terms of y and x but with dy/dx. There's no way of checking this without actually have to convert it back to y?
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    (Original post by Nikhilm)
    No, i mean when the question is given in as a differential equation, not in terms of y and x but with dy/dx. There's no way of checking this without actually have to convert it back to y?
    I don't understand, happen to have an actual question like this?
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    Name:  image.jpg
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    For 11b how is it done? I could see a pattern but then I could only see of making x=0 not 2 and then wasn't sure what to do with the r
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    When doing the inequality questions how do you know whether a particular algebraic fraction is negative? Its confusing me.
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    (Original post by Rkai01)
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    For 11b how is it done? I could see a pattern but then I could only see of making x=0 not 2 and then wasn't sure what to do with the r
    ln2?
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    (Original post by Rkai01)
    Name:  image.jpg
Views: 185
Size:  500.9 KBAttachment 543177543179
    For 11b how is it done? I could see a pattern but then I could only see of making x=0 not 2 and then wasn't sure what to do with the r
    Here's how I did it Name:  image.jpg
Views: 105
Size:  500.5 KB
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    (Original post by edothero)
    I don't understand, happen to have an actual question like this?
    I mean for when its solving a taylor differential equation
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    (Original post by A Slice of Pi)
    Yes
    What final 2 terms did you end up with for the method of differences?
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    (Original post by target21859)
    Here's how I did it Name:  image.jpg
Views: 105
Size:  500.5 KB
    Ah yeaa I was getting there but that is correct ln2 thanks a lot.
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    (Original post by Rkai01)
    What final 2 terms did you end up with for the method of differences?
    Is this for the question I made or the one Zacken made? One of them is in the solution I gave in a spoiler earlier. They should all vanish apart from the first and last if I remember rightly...
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    (Original post by target21859)
    Here's how I did it Name:  image.jpg
Views: 105
Size:  500.5 KB
    Would you happen to know how to go about 11b. I feel dumb because it's a hence question but I can't integrate with the sqrt and by substitution becomes awkward.
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    (Original post by A Slice of Pi)
    Is this for the question I made or the one Zacken made? One of them is in the solution I gave in a spoiler earlier. They should all vanish apart from the first and last if I remember rightly...
    No yours was fine it was zackens
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    (Original post by edothero)
    I don't understand, happen to have an actual question like this?
    Something like y'' + y' + y = ax + b, now give a series solution of y up to the term in x^3.
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    Someone please explain to me how to work with polar equatiions and finding the perpedicular/parallel line when you have r squared.
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    (Original post by A Slice of Pi)
    Is this for the question I made or the one Zacken made? One of them is in the solution I gave in a spoiler earlier. They should all vanish apart from the first and last if I remember rightly...
    How did you get it down to the second line please?
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    (Original post by Rkai01)
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Views: 185
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    For 11b how is it done? I could see a pattern but then I could only see of making x=0 not 2 and then wasn't sure what to do with the r
    do we have to know how to do these? they seem a lot harder than any of the exam qs

    can i ask how you would approach 9a?
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    (Original post by kkboyk)
    When doing the inequality questions how do you know whether a particular algebraic fraction is negative? Its confusing me.
    :hmmmm2: do you have an example of what you mean?
 
 
 
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