Recent content by cezarion

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    Very quick question: function signature

    Thank you for your reply. I think I understand your example for L = xy. If instead I take M = xy + yz can I write M = \frac{1}{2}(x + y)^2 - \frac{1}{2}(x - y)^2 + \frac{1}{2}(y + z)^2 - \frac{1}{2}(y - z)^2? We haven't covered eigenvalues yet in our course, so I'm not sure how to apply that...
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    Very quick question: function signature

    Thank you for your reply. The definition that I am supposed to use is given by http://mathworld.wolfram.com/QuadraticFormSignature.html I am not sure how to convert my linear series of terms into a signature though, seeing as how there are no squared terms.
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    Very quick question: function signature

    I was just wondering if somebody could give me a very quick definition and work through a short example. We have just covered quadratic forms, and one of the questions we have been given is on calculating signatures. I found several online references that say the signature relates to the...
  4. C

    Limit and partial derivatives proof

    Thank you for the reply. This was actually proved in our textbook, so I am just citing the result in the proof for this problem, leaving just the general case that needs to be proved.
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    Limit and partial derivatives proof

    Homework Statement Prove that if all partial derivatives up to order n are zero at \vec{x} and f(x) = 0 then \displaystyle\lim_{h \rightarrow 0} \dfrac{f(x + h)}{|h|^n} = 0 Homework Equations \displaystyle\lim_{h \rightarrow 0} \dfrac{f(x + h) - f(x)}{|h|} = 0 f(x) = 0 The Attempt...
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