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Current time: February 2, 2025, 7:04 am
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Maths test
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Wow. You fail at really simple maths.
Or you lied. Which are you, stupid or a liar?
Doesn't work. My favorite move is Saving Private Ryan, but I got Jaws instead...
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell
Mine isn't even on the list and I hate Saving Private Ryan..
"The Universe is run by the complex interweaving of three elements: energy, matter, and enlightened self-interest." G'Kar-B5
Very nice and interesting topic to check the intelligibly.Every person have to select the favorite subject but i like maths because We can examine our intelligence through it.mostly people have poor knowledge about maths.
RE: Maths test
May 27, 2013 at 9:56 am
(This post was last modified: May 27, 2013 at 9:58 am by little_monkey.)
I will prove that for every multiple of 9, the sum of its digit is 9.
To prove that, I will assume that the sum of its digit is 9, and prove that number must be a multiple of 9. I will demonstrate for a two digit number ( proof is the same for any number of digits, but longer) Let T be the digit for the tens, U be the digit for the units. Assumption: (1) T + U = 9 or (2) U = 9 - T (3) The number is N = 10 x T + U Substitute (2) into (3) (4) N = 10 x T + ( 9 - T) = 9 x (T +1) , which is always a multiple of 9 Therefore, the sum of the digit of a multiple of 9 is always 9. QED RE: Maths test
June 5, 2013 at 3:56 pm
(This post was last modified: June 5, 2013 at 3:58 pm by Categories+Sheaves.)
^ What he said.
If you're familiar with modular arithmetic, the general argument follows from observing that 10N (for nonnegative integers N) is always congruent to 1 mod 9. If we rewrite a = a0*100 + a1*101 + a2*102 +... i.e. express a in something like a decimal expansion, the residue of a mod 9 is the same as the sum of the residues of the an mod 9. This works in general (base j, going mod k) if you make sure to multiply an by the residue of jn mod k in the resulting sum. Since 10n is congruent to (-1)n mod 11, this is where you get that adding/subtracting digits thing for testing whether a number is divisible by 11. So you get something like the 9 rule for things that divide (j-1) and the 11 rule for things that divide (j+1).
I knew that
I still don't
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould |
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