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 Dec3 revised How to simplify $\frac{4 + 2\sqrt6}{\sqrt{5 + 2\sqrt{6}}}$? nominator->numerator Dec3 suggested approved edit on Limit of this indeterminate form. Dec3 suggested approved edit on For $z =\frac{ xy}{x+y}$, why is $z < x$ and $z < y$ for all values of $x > 0$ and $y > 0$? Dec3 suggested approved edit on How to simplify $\frac{4 + 2\sqrt6}{\sqrt{5 + 2\sqrt{6}}}$? Dec3 comment How to simplify $\frac{4 + 2\sqrt6}{\sqrt{5 + 2\sqrt{6}}}$? Isn't this how you show 5 equals 4? Aug16 comment Is addition more fundamental than subtraction? @Lee: and a metric is positive by definition. Aug15 awarded Popular Question Aug15 comment Is addition more fundamental than subtraction? @user1729 in my defense, I touched that aspect already in this comment Aug15 comment Is addition more fundamental than subtraction? A subtraction like this does not conform to the natural definition subtraction has. A metric is positive definite, subtraction is not. Aug15 awarded Nice Question Aug14 awarded Yearling Aug14 comment Is addition more fundamental than subtraction? @AustinMohr: I'll keep that in mind. Sorry about that. Aug14 comment Is addition more fundamental than subtraction? @Drise: completely equivalent after the isomorphic transformation. So in Math speak: completely equivalent. Aug14 comment Is addition more fundamental than subtraction? Reversing the two concepts just leaves you with two isomorphic concepts that does not answer the question. Aug14 asked Is addition more fundamental than subtraction? Jul31 comment What's the meaning of the unit bivector i? @draks that is not geometric algebra. That's Dirac algebra which only makes sense in Dirac theory. Geometric algebra promises (I'm still learning) to be applicable/useful everywhere, not just in the case of $\gamma$s. And an index $i$ is nothing evil. Jul31 awarded Critic Jul31 comment What's the meaning of the unit bivector i? @celtschk OK. But Hestenes maintains quaternions are just an aspect/transformation/... of the more general geometric algebra (at least in sofar they are used in Physics). I can't deduce any geometric meaning from quaternions either, so although insightful, it doesn't help me much (probably why you made it a comment anyways ;-)). Jul31 comment What's the meaning of the unit bivector i? OK. This is part of the meaning I get. The bivector as an operator is a rotor. But the bivector as basis element of the algebra should have a meaning on its own. Is my plane interpretation correct? Jul31 comment What's the meaning of the unit bivector i? It seems you avidly hate Hestenes' formulation. I get the parallel with $\gamma$ algebra the way you see it (I first came into contact with geometric algebra when studying the Dirac equation), but in the pdf referenced, he's not talking about $\gamma$ algebra, he's talking Euclidean geometry, where stuff like $\gamma$-matrices (he's not even talking about matrices) are not even relevant. You're giving a non-geometric interpretation IMHO, which is not quite what I'm after. I'm after the interpretation Hestenes describes.