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Re: Solve this math equation!
Posted: Fri Nov 20, 2009 9:12 am
by guyz92
flee0308 wrote:
No, no, thats not the point. This is not to show a=b. The point is to find the mistake in the equaion, and this is it.
Boredness wrote:I found this on the net...
Given: a = b
a^2 = ab
a^2 - b^2 = ab - b^2
(a+b) (a-b) = b(a-b)
(a+b) = b
(a+a) = a
2a = a
2 = 1
WTF?
If you look at step 3, you would know that both sides of the equation is divided by
(a-b). That cannot be done, as a=b, which means (a-b)=(a-a)=0. Division by Zero is not allowed in any case. Thus, the equation should be continued like this:
Given: a = b
a^2 = ab
a^2 - b^2 = ab - b^2
(a+b)
(a-b) = b
(a-b)
(a+b)(a-a)=b(a-a)
(a+b)*0=b*0
0=0
guyz92: There is NO such thing as "crossing out" in maths. "crossing out" is a just a more convenient mean of division. Further more, there is no Law of Indices about crossing out. Oh and there is a shorter step of solving the equation if it was a proving sum.
Proof that a=b from a^2=ab.
a^2=ab
Dividing both sides by a, a=b
(a+b)(a-b)=b(a-b)
(a+b)=[b(a-b)]÷(a-b)
Therefore it became (a+b)=b.
If above still dun understand, Sub (a-b) as big U.
(a+b)(U)=b(U)
(a+b)=[b(U)]÷(U)
(a+b)=b
PS this is not indices, it is sec 2 math.
Re: Solve this math equation!
Posted: Fri Nov 20, 2009 9:20 am
by Boredness
a-b = 0
b(a-b) = 1 x 0
= 0
Re: Solve this math equation!
Posted: Thu Dec 10, 2009 10:10 am
by flee0308
guyz92 wrote:flee0308 wrote: No, no, thats not the point. This is not to show a=b. The point is to find the mistake in the equaion, and this is it.
Boredness wrote:I found this on the net...
Given: a = b
a^2 = ab
a^2 - b^2 = ab - b^2
(a+b) (a-b) = b(a-b)
(a+b) = b
(a+a) = a
2a = a
2 = 1
WTF?
If you look at step 3, you would know that both sides of the equation is divided by
(a-b). That cannot be done, as a=b, which means (a-b)=(a-a)=0. Division by Zero is not allowed in any case. Thus, the equation should be continued like this:
Given: a = b
a^2 = ab
a^2 - b^2 = ab - b^2
(a+b)
(a-b) = b
(a-b)
(a+b)(a-a)=b(a-a)
(a+b)*0=b*0
0=0
guyz92: There is NO such thing as "crossing out" in maths. "crossing out" is a just a more convenient mean of division. Further more, there is no Law of Indices about crossing out. Oh and there is a shorter step of solving the equation if it was a proving sum.
Proof that a=b from a^2=ab.
a^2=ab
Dividing both sides by a, a=b
(a+b)(a-b)=b(a-b)
(a+b)=[b(a-b)]÷(a-b)
Therefore it became (a+b)=b.
If above still dun understand, Sub (a-b) as big U.
(a+b)(U)=b(U)
(a+b)=[b(U)]÷(U)
(a+b)=b
PS this is not indices, it is sec 2 math.
This is not indices. This is not sec 2 math. This is the very basic rule of division. You cannot divide by zero. Nor can you times 0 first, then divide by 0. 0/0 is neither 0, nor 1. It is undefined (or error2, if you use a calculator)
(a-b)=0, and you cant divide by 0.
Re: Solve this math equation!
Posted: Thu Dec 10, 2009 10:41 am
by iSean
Wow A Crap
My Brain Brust into Flames. Anyways you learn this crap in Singapore. In Malaysia Every Education Kinda Slow but less pressure
Re: Solve this math equation!
Posted: Sun Dec 20, 2009 11:54 am
by iZenna
iSean wrote:Wow A Crap
My Brain Brust into Flames. Anyways you learn this crap in Singapore. In Malaysia Every Education Kinda Slow but less pressure
iSean you're F4/5? add maths?
off topic:
i'm back
Re: Solve this math equation!
Posted: Sun Dec 20, 2009 12:53 pm
by iSean
I don't do add math since I never learn it
Malaysia Education in Math sucks I'm 12 And Nothing much to learn
Re: Solve this math equation!
Posted: Tue Dec 29, 2009 1:26 am
by flee0308
Yeah and Maths is not going to be taught in english soon lol.
Re: Solve this math equation!
Posted: Tue Dec 29, 2009 2:54 am
by iSean
Yup... If like that I need to work 5 times more after Form 4
=="