chisquared·2 年前·議論> We don't recommend oh-my-fish for various reasonsCare to elaborate a bit on those? Or is it the kind of thing that's impolite to discuss?
chisquared·2 年前·議論If b is negative, define c = -b, and use the linked result to show thata^2 - b^2 = a^2 - (-c)^2 = a^2 - c^2 = (a + c)(a - c) = (a + b)(a - b)
chisquared·2 年前·議論> Then you've just skipped the case when a^2 - b^2 is negative.Not really. If b > a, then swap them to conclude that b^2 - a^2 = (b + a)(b - a), which is what the visual proof demonstrates.Your conclusion is equivalent to saying that a^2 - b^2 = (a + b)(a - b).
chisquared·2 年前·議論Steve Jobs would have agreed with you at one point.I'm not sure what changed his mind (or if he ever even really did), but he also thought that aside from the native apps that came with the iPhone, everything else should just be a web app.
Care to elaborate a bit on those? Or is it the kind of thing that's impolite to discuss?