Question

1=2(1-n)!/(2-n)!.Find n ?​

Answer 1

Step-by-step explanation:

We have,

(n+2)!=60(n−1)

As we know n!=(n−1) n!

Therefore,

(n+2)(n+1)n×(n−1)!=60(n−1)!

(n+2)(n+1)n=60

(n2+2n+n+2)n=60

(n3+3n2+2n−60)=0

⇒n3+3n2+2n−60=0

Factoring the left hand side, this equation resolves to

(n−3)(n2+6n+20)=0(n−3)(n2+6n+20)=0

Since it can be shown that(n2+6n+20)=0 has (n2+6n+20)=0 no real solution, 

n−3=0

n=3

Hence, the value of n is 3.