how would u prove this using a formal proof?
Q. -5 x -5 = 25 Please dont give me such ridiculous answers, I want reasons.
Asked by 2447 - Thu Feb 7 14:30:46 2008 - - 2 Answers - 0 Comments

A. well, -5 x - 5 gives 25. 5 x 5 is always 25. Now why it is positive, I do not know. Like signs are ALWAYS positive. Unlike signs are ALWAYS negative. This applies to multiplication plication and division.
Answered by james w - Thu Feb 7 14:37:16 2008

Is there a way to "winter-proof" formal business attire?
Q. I am a man relocating to Boston to take a job with a formal business dress code. I will be walking to work and the T station (subway). I wear a suit and dress shoes everyday - but I've never had to walk to work dressed this way. Is there anything I can do help protect my clothes in inclement weather? Any recommendations for outerwear? Should I wear different shoes while I walk? Thanks for any and all suggestions.
Asked by Brad W - Wed Dec 17 15:28:41 2008 - - 5 Answers - 0 Comments

A. You could wear different shoes, yes, if there's snow this is an especially practical idea because otherwise your shoes will have tons of white on them from the salt residue, it never looks great. For staying warm, you can find many suits that are double lined for warmth, as the sales people they should be able to direct you to which items are made for cold climates. I tend to prefer sticking to the outerwear because otherwise it can be uncomfortably warm when you're indoors. Wool is excellent, go for something rather long, there are many long coats for men that are very nicely tailored and stylized, as well as designed to be very warm. Try them on, if they feel heavy and are made of wool, you should be good =o) Gloves and scarves will… [cont.]
Answered by am1432 - Wed Dec 17 15:49:00 2008

Formal Proofs As Seen From the World Of Physics?
Q. Since high school geometry is typically the first time that a student encounters a formal proof, this can obviously present some difficulties. It can also lead kids to think that two-column proof is the only kind of proof there is - yet that form of proof is almost never used by practicing mathematicians. It could be easier, if children encountered informal 'proofs' in earlier school years, and were required to justify their statements and reasoning. This of course would not be on such formal level as it is in high school, but simply a mindset of teaching mathematics where mathematical statements and truths are justified, there are explanations of where things come from, why something works - and the child also is asked to provide… [cont.]
Asked by CUNY - Sun Sep 9 18:45:09 2007 - - 2 Answers - 1 Comments

A. On the one hand, doing formal proofs forces you to be clear about what depends on what. On the other hand, it forces you to be a bit rigid, because there is an order of priorities: axioms are more basic than theorems, and some theorems depend on other theorems. There's nothing really wrong with that, of course, but for most scientific people, it's not specially useful to continually focus on what is more basic and what is less: In the real world, you may find that you need to switch your assumptions and be flexible. The proofs in Euclidean geometry don't allow for that, and for that reason I found them somewhat constraining and artificial. Example: Conservation of energy can first be understood in the context of Newtonian physics as a… [cont.]
Answered by nealjking - Tue Sep 11 12:30:55 2007