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prove that if
a^(n) - b^(n) = (a-b)[(a-b)^(n-1)+nk]
then "k" will come natural for n=any prime number.
Please provide the mathematical proof.

2006-10-09 03:08:49 · 9 answers · asked by rajesh bhowmick 2 in Science & Mathematics Mathematics

9 answers

let a = b+c
by binomial theoerm

(b+c)^ n has got n+1 terms and p th tern = nCp b^pc^n-k

all terms except b^n and c^n are having n as factor because n does not get cancelled in nCp as n is prime. additionally all of them except b^n has a factor c as it contains a power of c
add all of them and take n as a factor also c

so (b+c)^n = b^n + c^n + nck
put b+ c = a

a^n = b^n +(a-b)^n+n(a-b) k
a^n-b^n = (a-b)^n + n(a-b)k
= (a-b)((a-b)^n-1 + nk)
QED

2006-10-09 03:56:39 · answer #1 · answered by Mein Hoon Na 7 · 0 0

For binomial property

(a-b)^n = nc0 a^n - nc1 a^n-1 b + nc2 a^n-2 b^2 - nc3 a^n-3 b^3 + ---------- (-1)^n nc(n-1) a b^n-1 - ncn b^n ----------- (1)
(a+b)^n = nc0 a^n + nc1 a^n-1 b + nc2 a^n-2 b^2 + nc3 a^n-3 b^3 + ---------- nc(n-1) a b^n-1 + ncn b^n ---------------(2)

Now subtract (2) - (1)and take your inputs. After simplefication we get the result

a^n - b^n = (a-b) [(a-b)^n-1 + nk]

2006-10-10 03:13:39 · answer #2 · answered by Hari 1 · 0 0

You said it was important. Did you wanted a dark magician for answering this kind of question? Huh.......

2006-10-09 10:25:36 · answer #3 · answered by Anonymous · 0 1

after some trivial manipulations i get :

nk (a-b) = a^(n) - b^(n) - (a-b)^n

since a-b | a^(n) - b^(n) - (a-b)^n

k is natural since n is and lhs is.

now go after the girls.

2006-10-10 03:15:17 · answer #4 · answered by gjmb1960 7 · 0 0

umhh sorry i am poor in mathematics

2006-10-09 10:41:56 · answer #5 · answered by rakesh n 2 · 0 0

You said it was important!!!

2006-10-09 10:10:00 · answer #6 · answered by Anonymous · 0 2

yeah u wasted my time too!

2006-10-09 10:11:34 · answer #7 · answered by Anonymous · 0 2

do your own homework

2006-10-09 10:11:16 · answer #8 · answered by Anonymous · 0 2

D-UH!

2006-10-09 10:18:20 · answer #9 · answered by fleur 4 · 0 1

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