Q. 20 A4.7( 3 Votes )

# Let r and n be positive integers such that 1 ≤ r ≤ n. Then prove the following:

Answer :

Given that we need to prove

Consider L.H.S,

We know that

And also n! = n(n – 1)(n – 2)…………2.1

⇒

⇒

⇒

= R.H.S

∴ L.H.S = R.H.S, thus proved.

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Prove that the product of 2n consecutive negative integers is divisible by (2n)!

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