1. Evaluate the numbers for the coefficient of x(adsbygoogle = window.adsbygoogle || []).push({}); ^{4}y^{9}in the expansion of (3x + y)^{13}.

2. The Binomial Theorem states that for every positive integer n,

(x + y)^{n}= C(n,0)x^{n}+ C(n,1)x^{n-1}y + ... + C(n,n-1)xy^{n-1}+ C(n,n)y^{n}.

3. I understand that the coefficients can be found from the n row of Pascal's triangle, where n = 13. Using the binomial theorem, my approach (which I'm not sure about) is:

The coefficient is 3 * C(13,9) = 3 * 715 = 2145.

Am I going about this correctly? Sorry if I didn't expand on the proof.

surferstrobe

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# Homework Help: Pascal's Triangle and Binomial Theorem

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