SOS for mathematicians.

[judo guy]

My friends son just gave me an algebraic problem that seems to prove 1=0. It seems to conform to all the rules. Tell me where it is wrong

Let A=B=1

1) A=B

2) A squared=AB

3) A squared - B squared = AB -(B squared)

4) (A + B)(A-B)= B(A-B)

5) A + B = B

6) A = 0

7) 1 = 0

Being stoned during algebra class finally caught up with me.

Where is the fault in the problem?

[YeLLa-TiGeR]

ugh......math

[SanDiegoBJJ]

youre wrong at 5-a+b=2--if a=b=1, then it would be 1+1=2

[judo guy]

San Diego,

Thanks, I saw that also. But, step 4 looks correct to me. If step 4 is correct then step 5 is true (subtract a-b from both sides you are left with A + B = B). Can someone tell me what previous step is false? I have a feeling it is in step 4, but step 4 seems a logical progression from steps 1-3.

[Edited by judo guy on 11-11-2000 at 07:43 PM]

[Hung Lo]

In step 4 you're factoring out a zero (A - B = 0)

Anything divided by zero is undefined.

[judo guy]

Thanks Hung Lo. I thought dividing by zero was an illegal step, but I wasn't sure. Damn I feel stupid.

[Edited by judo guy on 11-11-2000 at 07:56 PM]

[Bad Karma]

Are you kidding?

You just got answered and I STILL don't know what you're talking about!

Peace

[SweepEm]

Besides in school,
I have yet to use one algebra formula in real life.

hey Judo Dude, don't tell your son that.
You never know when your life might depend on the algebra, trigonometry and caluculus you've learned in school.

[Ronin]

Yeah, but SweepEm...you're old, dude!

I mean, did they even have computers when you graduated from high school? I mean, besides Robbie the Robot and those gigantic buildings that helped guide the Apollo rockets?

Sorry, you're the one Forum "lifer" whom I haven't antagonized yet in the year+ I've been posting.