Jason
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 Oct 19 awarded Famous Question Sep 7 awarded Nice Question Mar 25 awarded Notable Question Feb 4 awarded Popular Question Jul 2 awarded Curious May 7 awarded Notable Question Apr 23 accepted How do I begin proving this binomial coefficient identity: ${n\choose 0} - {n\choose 1} + {n\choose 2} - {n\choose 3} + \dots = 0$ Apr 22 comment How do I begin proving this binomial coefficient identity: ${n\choose 0} - {n\choose 1} + {n\choose 2} - {n\choose 3} + \dots = 0$ That was the answer at the back of the book. But I don't get what just that statement means. Is that a proof to just "say" that? Apr 22 asked How do I begin proving this binomial coefficient identity: ${n\choose 0} - {n\choose 1} + {n\choose 2} - {n\choose 3} + \dots = 0$ Mar 14 awarded Notable Question Feb 25 awarded Popular Question Dec 1 awarded Popular Question Sep 27 awarded Yearling Jul 29 awarded Popular Question Jun 13 accepted Probability of adjacent seating Jun 13 asked Probability of adjacent seating May 15 accepted Basic independent probability question May 15 comment Basic independent probability question Okay, according to the definition there (and Google), so it is times, which means it's $^$. Thanks. May 15 comment Basic independent probability question Hmm...the probability the purse won't hold them all is the probability that all three coins come up heads (as you mentioned). But what is that, in math? Okay well it can't be $1/2 + 1/2 + 1/2$ because that probability would be $> 1$. So is it really $1/2 * 1/2 * 1/2$? Isn't there something about adding independent events and multiplying dependent events? Or are these events dependent? Or have I got it hopelessly wrong? May 15 revised Basic independent probability question added 167 characters in body