Re Nagging Math Problem.?
92491
OK, first off no one seemed to be able to answer the dividing by 0 and 1 issue correctly, so here goes...\n\nDivision by n is defined as multiplication by the multiplicative inverese of n.  The multiplicative inverse of n is defined as the number 1/n such that n*(1/n)=1.  Zero has no multiplicative inverse because 0 times anything is 0.  Therefore division by zero implies multiplication by a number that does not exist.  One does have a multiplicative inverse (1x1 = 1), so division by 1 is perfectly valid, although you are correct that the result is the number which was divided by 1.  It is exactly the same as multiplying by 1.\n\nNow on the area of a circle issue...\n\nYou seem to be trying to relate area to circumferance.  It's not hard.\nLet A = the area of the cirlce, c = the circumferance, and r = the radius.\nYou already know that A=(pi)r^2 and c=2(pi)r.\nSolve the second equation for r and get r=c/(2pi).\nNow substitute that into the first equation to get A=(pi)(c/(2pi))^2.\nThen simplify and you get A=(c^2)/(4pi).\n\nLike it or not, you can't get rid of the pi.  Pi is defined as the ratio of the diameter of a circle to its circumference, so it's going to be there no matter what.  When you say it's useless unless you know all the digits, this simply isn't true.  Depending on what you're doing, you can either get the pi's to cancel out, or you will be finding a decimal approximation of the area or circumference.  If the radius is a whole number, the area simply won't be (there may be a few values for which it will be, but most of the time it isn't), and any formula you come up with that says otherwise is incorrect.\n\nAs for the sphere question, I don't understand what you're asking.  Are you trying to equate area to volume?  They're not the same thing.  You can't find the area by sticking together infinitely thin slices as the slices have no height so you will never have a third dimension.  You might be able to do it using limits, but that's not going to be the kind of nice simple numbers you're looking for.  If you can explain what you meant, I might be able to do a bit better.
233465
A.) (4*3) / (11*10) = 0.10909090909090909090909090909091\nB.) (7*6) / (11*10) = 0.38181818181818181818181818181818\nC.) this can be treated in 3 cases:\n\n(i) both defective (similar to letter A)\n    (4*3) / (11*10) = 0.10909090909090909090909090909091\n\n(ii) first is defective second is not\n    (4*7) / (11*10) = 0.25454545454545454545454545454545\n\n(iii) first is not defective second is\n    (7*4) / (11*10) = 0.25454545454545454545454545454545\n\nTake the sum of the 3 cases and you'll get 0.61818181818181818181818181818091
1017997
The equations are wrongor insufficient. Post the correct data if you want me to help/ Alternately, you could also message me.
1025788
do you mean 18 times the sq rt of 50, that would be 127.3\nthen subtract 21 times sq rt 40 divided by 3 times sq rt 2\nOr, is all of the subtraction part above the line\nSee if you can rewrite the problem
843943
4, 0, -2, -2, 0\n\nFigure it out! Don't be lazy!
285246
hey this is the math section\nthere is an another section for this type of question\nu had better post it their 4 a better response
891258
Try 1 ÷ 3\n\n1/3 = 0.33333.....\n\n~ ♥ ~
281150
Next time just type your math equation into Google and it will do the math for you.\n\n15
840437
Well, I can see that one possible solution is r = 0, and my calculator says the other answer is r = 0.0809394063, so hopefully that helps...
830625
About -37.21\n\nYou want the two terms to be 10 apart...Upon inspection you know t MUST be negative, since the second term can not be greater than the first term.\n\nSo if the two are equal t = -36.55, so through trial and error I got -37.21
959479
all you need to do is go to www.webmath.com, it'll help u there!\n\nI always do my math problems to that site if ever i get stuck on something! It's helpful!
133517
the solutions is 7,8,3,2 or 7,6,5,2. The problem works with both sets of numbers.
898860
First one: d= - 1\n\nEDIT: the rest I'm too lazy to do. Do your own homework! =D
1081089
[ (50000 x 2.4)+(25000 x .8) ] / (50000+250000)=1.8\n\nThe remainder of the info in the problem is not necessary.
1020883
i am sure you can find a math tutor that will be happy to help you when you explain what the problem is.\n\nso what IS the problem, anyway?
302992
2 x 2 = 4\nHe asked for square, not square root.
148434
So, continuing with mr_w's excellent example, we have 4 equations in 4 unknowns. So you can set this up as a matrix-vector problem.  Define matrix M such that M * Number of games bought vector = Cost & total games vector.  Assigning the rows of M in order to the total cost, the PS3 and Xbox360 cost, the PS1 and Xbox360 cost, and the total number of games, \nM = \n70 150 300 450\n0 0 300 450\n70 0 0 450\n1 1 1 1\nNumber of games bought vector =\na\nb\nc\nd\nand Cost & total games vector =\n13910 12000 3050 54\nThe solution will find the values of a, b, c and d.\nWhen I ran the solution I ended up with noninteger values for each and the values checked with the problem statements.  I hope those values were mr_w's solution.