No products in the cart.

Show that n square -1 is …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Show that n square -1 is divisible by 8, if n is a positive integer. Explain breifly guys plzz???
  • 1 answers

Ram Kushwah 6 years, 9 months ago

The question is like this:

Show that n2 - 1 is divisible by 8, if n is an odd positive integer

Soln:Any odd positive integer n can be written in form of 4q + 1 or 4q + 3.

 

If n = 4q + 1, then

 n2 - 1 = (4q + 1)2 - 1 = 16q2 + 8q + 1 - 1 = 8q(2q + 1) which is divisible by 8.

If n = 4q + 3,then

 n2 - 1 = (4q + 3)2 - 1 = 16q2 + 24q + 9 - 1 = 8(2q2 + 3q + 1) which is divisible by 8.

 

So,  n2 - 1 is divisible by 8, if n is an odd positive integer.

https://examin8.com Test

Related Questions

sin60° cos 30°+ cos60° sin 30°
  • 2 answers
Venu Gopal has twice
  • 0 answers
Prove that root 8 is an irration number
  • 2 answers
X-y=5
  • 1 answers
(A + B )²
  • 1 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App