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FP2 - second order differential - substituition watch

    • Thread Starter

    Hi all,

    I'm trying to get my head around solving second order differential equations using substitution.

    In a lot of these questions, they seem to use implicit differentiation at various points through the question. Take this example from the Edexcel FP2 book:

    Name:  FP2 - Substitution.jpg
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    In their solution they start by doing:

    Is it not easier/possible to use implicit differentiation straight away:

    Most questions seem to have you differentiating and using the chain rule to get your desired differentials, but can you jump straight in and use implicit differentiation to get what you want (in this case dy/dx)?
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    • Study Helper

    Study Helper
    (Original post by Sir_Malc)
    Is it not easier/possible to use implicit differentiation straight away:
    Some of your attachments don't seem to work. That said: Yes, it's fine to use implicit differentiation. I can see the last attachement (y=z/x to xy = z,....), and that's fine.
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Updated: November 12, 2015
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