find the Coefficient of termxin below expansion:^{2}y^{3}

expansion :(2+x-y+3z)^{10 }^{please write a good description for solution* or how to solve it? * for a person who is a dummy in math and combinatorics...}

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- Feb 28th 2013, 12:40 AMmshouCoefficient and expansions.
find the Coefficient of term

**x**in below expansion:^{2}y^{3}

expansion :**(2+x-y+3z)**^{10 }^{please write a good description for solution* or how to solve it? * for a person who is a dummy in math and combinatorics...} - Feb 28th 2013, 01:09 AMjakncokeRe: Coefficient and expansions.
80,640. Use the multinomial theorem which says (Basically sum over all non negative integer partitions of n.)

the

basically, it says the powers on the exponents of each term you have in your parenthesis, namely 2,x,y,z must add up to 10.

so how you can write 10 = 0+0+3+7 which is equivalent to

so since you asked for this means since we don't see z so the power of z is 0. 2+3+0+x = 10 and so x = 5 (which is the power 2 is raised to)

so you have = 80640 - Feb 28th 2013, 01:25 AMMINOANMANRe: Coefficient and expansions.
It is - 80640 x^2y^3

MINOAS - Feb 28th 2013, 01:28 AMmshouRe: Coefficient and expansions.
well. thanks and a question:

isn't there any difference between for instance 3x and x, and -y and y ? - Feb 28th 2013, 01:43 AMmshouRe: Coefficient and expansions.
well. thanks and a question:

isn't there any difference between for instance 3x and x, and -y and y ?