Evaluate 2C2?

We have to evaluate the expression C²₂

Solution

To evaluate the expression C²₂ we use the following formula

nCr =n! / r! (n – r)!

n = 2
r = 2

Substitute n and r values in above formula

nCr =n! / r! (n – r)!

C²₂= 2! / 2! (2-2)!

C²₂= 2! / 2! (0)!

Find the factorial for 2!, 2! & 0!, substitute the corresponding values in the below expression and simplify. We have learnt that 0! = 1

=2 X 1 / (2 X 1) (1)

= 2/ (2 )

= 2 / 2

= 1
C²₂= 1

Answer

C²₂= 1