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Need help with this series approximation. watch

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    Fill in the values for p,q and r in this series approximation. Use decimals, or a fraction with integers top and bottom, so 0.75 OR 3/4.

    (a^3)/(a^2-x^2)^1.5 = p +q(x^2/a^2) + r(x^2/a^2)^2
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    (Original post by sidhi12)
    Fill in the values for p,q and r in this series approximation. Use decimals, or a fraction with integers top and bottom, so 0.75 OR 3/4.

    (a^3)/(a^2-x^2)^1.5 = p +q(x^2/a^2) + r(x^2/a^2)^2
    I presume you're comfortable with the expansion of (1+x)^n, where the constant term is "1".

    Here you have a^2. So, you need to extract a factor first of all to get it into the desired from (1+ ...).
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    (Original post by ghostwalker)
    I presume you're comfortable with the expansion of (1+x)^n, where the constant term is "1".

    Here you have a^2. So, you need to extract a factor first of all to get it into the desired from (1+ ...).
    I've done up to there and got the expansion. However when I divide the a^3 by the expansion, I don't end up with an expression like the one with the p,q and r
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    (Original post by sidhi12)
    I've done up to there and got the expansion. However when I divide the a^3 by the expansion, I don't end up with an expression like the one with the p,q and r
    You shouldn't need to divide by the expansion.

    (a^3)/(a^2-x^2)^1.5 = (a^3)(a^2-x^2)^-1.5

    and your expansion is in the numerator.
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    Thanks
 
 
 
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