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how can you prove that (a*b)^2 = a^2*b^2

2007-01-11 01:09:14 · 7 answers · asked by nikos k 1 in Science & Mathematics Mathematics

7 answers

You can prove (ab)^n = a^n * b^n for all n, using induction. It's been done for n=2 by lots of people here, the next step is proving that if it's true for a given n, it's also true for n+1.

So, given (ab)^n = a^n * b^n for some n, we have
(ab)^(n+1)
= (ab)^n * (ab)^1 (expanding)
= a^n * b^n * ab (by hypothesis)
= a^n * a * b^n * b (rearranging factors)
= a^(n+1) * b^(n+1).
QED.

2007-01-11 01:33:53 · answer #1 · answered by Anonymous · 1 0

Simple.

First - squaring means multiplying by itself

(a * b) * (a * b)

As it is all multiplication the brackets aren't needed

a * b * a * b

You can rearrange the terms

a * a * b * b

Again, looking at what squaring means. This is the same as a^2 * b^2

2007-01-11 09:19:33 · answer #2 · answered by Tom :: Athier than Thou 6 · 0 0

Go to class 5

2007-01-11 09:30:54 · answer #3 · answered by Anonymous · 0 0

Take examples as
a=2, b=3 then find
LHS -
a*b= 2*3=6
(6)^2=36 ---------{1}
RHS-
(a)^2=2^2=4
(b)^2=3^2=9
(a)^2*(b)^2= 4*9=36-----------{2}
Therefore {1} ={2}

2007-01-11 09:27:22 · answer #4 · answered by Haritha 2 · 0 1

LHS
=(a*b)^2
=(a*b)*(a*b)
=a*b*a*b
=a*a*b*b
=a^2*b^2
=RHS (proven)

2007-01-11 09:16:34 · answer #5 · answered by leafinthewind 1 · 0 0

(ab)^2=(ab)(ab)
rearrange the terms
=aabb=a^2 b^2

2007-01-11 09:12:06 · answer #6 · answered by Professor Maddie 4 · 1 0

If greek please e-mail me!!!

(a*b)^2=a^2*b^2

(a*b)^2
=(a*b)*(a*b)
=a*b*a*b
=a^2*b^2

2007-01-11 09:25:28 · answer #7 · answered by Bill 1 · 0 0

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