[Jesus]

2x + 3y + z = 0
x − 2y − z = −3
x + y + 2z = 3

Solution:

octave:1> A = [2,3,1,0;1,-2,-1,-3;1,1,2,3]
A =

2 3 1 0
1 -2 -1 -3
1 1 2 3

octave:2> rref (A)
ans =

1 0 0 -1
0 1 0 0
0 0 1 2

That is
x = -1
y = 0
z = 2



I can't come up with anything funny, and there are still some problems left, this is the new one however:

What is a?
(2a-5)/6 = 5/12

[qtwerp]

(2a-5)/6 = 5/12
2(2a-5) = 5
4a - 10 = 5
4a = 15

a = 15/4

-------

A word problem.

In order to finish a 50m dash, a runner must first pass the midpoint, 25m. To reach 25m, he must first reach the 12.5m mark, and so on. So, the runner must reach an infinite amount of midpoints in a finite amount of time. Doing so is impossible, so the runner can never even begin his race.

What's wrong here?

[Jesus]

A hint/additional information for those who want to try and answer qtwerp's question:
Zeno's paradoxes - Wikipedia, the free encyclopedia

[bns]

Originally Posted by Jesus -1 and 3 Whats wrong: i = (-1)^{1/2} = ((-1)^{3})^{1/2} = (-1)^{3/2} = ((-1)^{1/2})^{3} = (i)^{3} = -i \Rightarrow 1 = -1

Well, with this one you're using a function that isn't well-defined. i=(-1)^{1/2} is not true in general.

Whats wrong: x^2 - x^2 = x^2 - x^2 x(x - x) = (x - x)(x + x) x = (x + x) x = 2x \Rightarrow 1 = 2

The classic divide by 0. (x-x)=0, therefore dividing by it is not a valid operation.

[metaphor-]

dont forget to post a new problem guys!

here is one.
Traffic flow is defined as the rate at which cars pass through an intersection, measured in cars per minute. The traffic flow at a particular intersetion is modled by the function F defined by:

F(t)= 82+ 4sin(x/2) for 0t30,

where F(t) is measured in cars per minute and t is measured in minutes.

To the nearest whole number, how many cars pass through the intersection over the 30 minute period?