4 ms·
Grab a Calculus book and solve some random problems. It can get fairly entertaining. Solving how much rocket fuel you need to reach orbit or how fast a conica
by parfe 16y ago
Grab a Calculus book and solve some random problems. It can get fairly entertaining. Solving how much rocket fuel you need to reach orbit or how fast a conical object will drain or the angle you need to fire a canon ball into a castle wall or something. I haven't found much use for Calculus though in regular life.
On a side note, we've been arguing about 48÷2(9+3) at the office today. There is a correct answer, of course, but also an argument (that some think is reasonable) against that answer.
- e03179 16y ago48÷2(9+3) = 2
- nlco 16y agonot quite, 48÷(2(9+3)) = 2, but 48÷2(9+3) = 288 to clarify: PEMDAS is the order of operations. so parenthesis first: 48÷2(9+3) = 48÷2(12) then multiplication and division (they have the same precedence): 48÷2(12) = 24*12 = 288 for another reference: http://www.google.com/search?q=48%C3%B72(9%2B3) http://www.google.com/search?q=48%C3%B72(9%2B3)
- dcosson 16y agomultiplication and division have the same precedence, and division (like most operations) is left-associative. For example, exponentiation is right-associative, so 2^3^2 = 2^9 = 512, not 64.
- wging 16y agoWhile you're technically correct, of the standard four half (+, *) are both left- and right-associative. / and - are the ones that are only left-associative.
- sga 16y agoBest bet is to replace x÷y by x*(1/y) as division is not commutative while multiplication is commutative. Therefore 48÷2(9+3) => 48(1/(2(9+3)) => 2
- wging 16y agoYou've still failed to correctly apply associativity, unfortunately. You're treating 2(9+3) as a single unit, but ÷ appears before the implicit multiplication between 2 and (9+3) and so should get evaluated first. The division should get simplified first with its immediate operands, 48 and 2. This yields (48÷2) * (9+3).
- nostrademons 16y agoIt's funny, the top Google result for [juxtaposition precedence] is exactly this question, posted on the PhysicsForum boards. 2 is actually leading 288 by a hair there. http://www.physicsforums.com/showthread.php?p=3235154 http://www.physicsforums.com/showthread.php?p=3235154 Anyway, the answer depends completely on whether you believe that multiplication by juxtaposition has the same precedence as multiplication by explicit symbol. There're good reasons to believe it doesn't, eg. the first post on that linked thread, but whatever the answer, it's entirely based on typographical convention. I don't work in the community that cares, so I don't really have an opinion, other than to point out it's not as cut-and-dried as virtually ever poster here believes. In the community that I do work, people who write parsers, things like this have to be explicitly specified. That's why I maintain that the correct answer is "syntax error".
- parfe 16y agothe real answer is that thw juxtaposition rules are made up on the spit by people trying to rationilze their incorrect answer . there is not and never had been a n "implit mulitplication" rule in the irder if operations. sent frim my drunk phone
- nostrademons 16y agoThey did, however, cite sources (possibly made up almost on the spot), which is more than anyone on this thread has done.
- ddlatham 16y ago
- deleted 16y ago[deleted]
- parfe 16y ago48÷2(9+3) = 288 If anyone cares. We can poll it up.
- nostrademons 16y agoSyntax error: expected operator but found '(' at line 1, column 5.