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#1 2006-10-10 03:55:29
- unique
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- Registered: 2006-10-04
- Posts: 419
simplify......am i right?
3 - sqrt(2)
------------
4 + 2sqrt(2)
i did
cross out similar numbers
cross out srt(2)
leaving
3
-------
4 + 2
4+2 = 6
3
--
6
leaving
1/2
correct
Desi
Raat Key Rani !
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#2 2006-10-10 04:03:48
- mathsyperson
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- Registered: 2005-06-22
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Re: simplify......am i right?
Sorry, it's not as simple as that. You can only cross out similar numbers like that if all the terms in the fraction are multiplied together. If they're added then it won't work.
I need to go now, so I can't do it all for you, but I can tell you that here 'simplify' means 'rationalise the denominator'.
Multiplying both sides by (4 - 2√2) would help immensely, I'd imagine.
Why did the vector cross the road?
It wanted to be normal.
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#3 2006-10-10 04:18:08
- unique
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- Registered: 2006-10-04
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Re: simplify......am i right?
ok see what i have done
you said multipy right
so 3 - sqrt(2) * 4 - 2sqrt(2) equals...12 - 4
because 2sqrt2 times sqrt2 equals 4
and then
4 + 2sqrt(2) * 4 - 2sqrt(2) equals... 16 - 8
so then
12 - 4
-------
16 - 8
12 - 4 is 8
and 16 - 8 is 8
so
8/8 is 1
Desi
Raat Key Rani !
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#4 2006-10-10 04:27:29
- luca-deltodesco
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- Registered: 2006-05-05
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Re: simplify......am i right?
3 - sqrt(2)
------------
4 + 2sqrt(2)
The Beginning Of All Things To End.
The End Of All Things To Come.
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#5 2006-10-10 04:32:06
- unique
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Re: simplify......am i right?
ok so my way was wrong then
Desi
Raat Key Rani !
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#6 2006-10-12 12:49:16
- fusilli_jerry89
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- Registered: 2006-06-23
- Posts: 86
Re: simplify......am i right?
unique wrote:3 - sqrt(2)
------------
4 + 2sqrt(2)
for the very beginning part when u times the fraction by the "negative" version of the denominator, is that technique only used for this stuff? It seems if you use that on any other question itll work also.
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#7 2006-10-12 17:36:31
- luca-deltodesco
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- Registered: 2006-05-05
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Re: simplify......am i right?
its just a technique for rationalising the denominator (removing any surds)
if its just a fraction like
you just need to multiply both sides by √b
but if you have a fraction lie
you have to multiply both sides by b -/+ √c
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#8 2006-10-13 01:15:21
- unique
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- Registered: 2006-10-04
- Posts: 419
Re: simplify......am i right?
ok i understand now 
thanks you guys
Desi
Raat Key Rani !
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