\(\frac{n^2-1}{n-2}\) ≥8
Whenn≤2
n^2-8n+15≤0
n=[3,5]
Not possible
Whenn≥2
n^2-8n+15≥0
n=[2,3]∪[5,∞ ]
Statement 1
n is odd number
When n>1,\(\frac{n^2-1}{n-2}\) ≥8
When n≤1,\(\frac{n^2-1}{n-2}\) ≤8
Statement 2- n>1
ifn=[1,2)∪(3,5), \(\frac{n^2-1}{n-2}\) ≤8
ifn=[2,3]∪[5,∞), \(\frac{n^2-1}{n-2}\)≥8
Combining both equations
n is odd number and greater than 1
\(\frac{n^2-1}{n-2}\) ≥8 is always true.
Sufficient.
If n ≠ 2, is \(\frac{n^2-1}{n-2}\)≥8 ?
(1) n is an odd number
(2) n > 1
...
Whenn≤2
n^2-8n+15≤0
n=[3,5]
Not possible
Whenn≥2
n^2-8n+15≥0
n=[2,3]∪[5,∞ ]
Statement 1
n is odd number
When n>1,\(\frac{n^2-1}{n-2}\) ≥8
When n≤1,\(\frac{n^2-1}{n-2}\) ≤8
Statement 2- n>1
ifn=[1,2)∪(3,5), \(\frac{n^2-1}{n-2}\) ≤8
ifn=[2,3]∪[5,∞), \(\frac{n^2-1}{n-2}\)≥8
Combining both equations
n is odd number and greater than 1
\(\frac{n^2-1}{n-2}\) ≥8 is always true.
Sufficient.
shridhar786 wrote:
If n ≠ 2, is \(\frac{n^2-1}{n-2}\)≥8 ?
(1) n is an odd number
(2) n > 1
...









