maths problem?
#1
Posted 26 April 2007 - 03:16 AM
l x - 3a l > l x - a l
ok.. i've been staring at this for a while now.. and i have no idea how to do this..
anyone can help me out here?
oh, and the "l l" is the modulus.
=)
i'm sure there are quite a few maths geniuses here in boajjang, right? ><
#2
Posted 26 April 2007 - 04:56 PM
| X - 3a | > | X - a
Sub a = 1
| X - 3 | > | X - 1 |
Sub X = 1
| 1 - 3 | > | 1 - 1 |
2 > 0
Though I'm sure you've already thought of this lol. Simple try and error.
Edited by sennheiserlover, 26 April 2007 - 04:57 PM.
#3
Posted 26 April 2007 - 08:02 PM
If it is then...yeah I think this would be basic algebra
But the problem is that im not sure kheewei would give out an easy question like this, especially since it
says its on a cambridge paper.
So wait, whats a modulus?
Edited by Dr. Rockso, 26 April 2007 - 08:03 PM.
#4
Posted 26 April 2007 - 08:19 PM
what kind of math is this???
#5
Posted 26 April 2007 - 09:16 PM
#6
Posted 26 April 2007 - 10:32 PM
#7
Posted 26 April 2007 - 11:00 PM
A real, positive quantity that measures the magnitude of some number. For instance, the modulus of a complex number is the square root of the sum of the squares of its components. Often it means, simply, the numerical (â€œabsoluteâ€) value of an algebraic quantity x.
so it is the absolute value...why cant every one use that terminology instead of
modulus; its really confusing because of that. That makes everything easier.
Edited by Dr. Rockso, 26 April 2007 - 11:00 PM.
#8
Posted 27 April 2007 - 01:40 AM
#9
Posted 27 April 2007 - 02:12 AM
X < 2
| X - 3a | > | X - a
Sub a = 1
| X - 3 | > | X - 1 |
Sub X = 1
| 1 - 3 | > | 1 - 1 |
2 > 0
Though I'm sure you've already thought of this lol. Simple try and error.
erm..
how'd you deduce that x<2 from 2>1?
edit: oh wait, is it becuase when you sub anything larger than 2 for x, it doesn't satisfy the inequality?
edit2:wait, that can't be right either, cause then you'll get a different answer for every a that you substitue in.
here's what i got (and think it's wrong, but now after seeing your solution, think it may, just may be correct)
x < 2a
what do you think?
Edited by kheewei, 27 April 2007 - 02:25 AM.
#10
Posted 27 April 2007 - 06:50 PM
X < 2a seems to fit the equation. Lol.
#11
Posted 28 April 2007 - 07:37 AM
i think ur supposed to do something to get rid of the absolute values....
l x - 3a l > l x - a l
(x - 3a) < -(x - a) and -(x - 3a) > (x - a)
treat the '>' like an equal sign and solve both...
i THINK its something like this but i ain't too sure.
Edited by babet, 28 April 2007 - 07:57 AM.
#12
Posted 05 May 2007 - 07:27 PM
#13
Posted 05 May 2007 - 07:51 PM
*sigh* Why can't math be this easy?
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