# No. of distinct 4 letter words from mathematics.

• Nov 18th 2011, 05:23 AM
prasum
No. of distinct 4 letter words from mathematics.
no of 4 DISTINCT Letter words from MATHEMATICS

USING MULTINOMIAL THEOREM I GET

coefficent of x^4 in ((1+x)^5) *((1+x+x^2)^3)
can yu help me find the coefficient of x^4 in this
• Nov 18th 2011, 07:01 AM
Soroban
Re: four letter
Hello, prasum!

If I read the problem correctly, you are complicating it.

Quote:

Number of 4-letter words with distinct letters from MATHEMATICS.

There are eight distinct letters:. $\{A,C,E,H,I,M,S,T\}$

We select and permute 4 of them.

Answer: . $_8P_4 \:=\:\frac{8!}{4!} \:=\: 1680$