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Couple binomial Things
First, can some tell me if I did this right, and if not, tell me what I did wrong.
expand (x+4y)^5
I got: x^5 + 20x^4y + 26x^3y^2 + 74x^2y^3 + 261xy^4 + 1024y^5
Second, I've forgotten the formulas for exponential growth and decay, If someone could provide those I'd greatly appreciate it.
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using the binomial formula:
^5 = \sum\limits_{k = 0}^5 {\left( {\begin{array}{*{20}c}<br />
5 \\<br />
k \\<br /> <br />
\end{array} } \right)} x^{5 - k} \left( {4y} \right)^k \hfill \\<br />
\hfill \\<br />
where:\quad \left( {\begin{array}{*{20}c}<br />
5 \\<br />
k \\<br /> <br />
\end{array} } \right) = \frac{{5!}}<br />
{{k!\left( {5 - k} \right)!}}\quad \hfill \\ <br />
\end{gathered} <br /> <br />
)
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ummm
I used Pascal's triangle, I was wondering if my numerical coefficients are correct mostly, what you said went over my head, thanks for trying to help me anyways :) and still looking for exponential growth and decay formulas, they have something to do with half-life I think.
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