Difference between revisions of "A choose b"

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== Why is it important? ==
 
== Why is it important? ==
a choose b is the formula for counting the number of ways you can pick b things from a group a things. For example, how many ways can you pick a group of 5 people to do a certain job from 8 people. Using our formula we see that <math>\frac{8!}{5!(8-5)!}=\frac{8!}{5!(3)!}= frac{\(8)(7)(6)}{3!}=frac{\(8)(7)(6)}{6}=8(7)=42</math>
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a choose b counts the number of ways you can pick b things from a set of a things. For example $\binom{8}{2}=\frac{8!}{2!(8-2)!}

Revision as of 16:50, 15 June 2019

Here is the formula for a choose b: $\binom{a}{b}=\frac{a!}{b!(a-b)!}$. This is assuming that of course $a \ge b$.

Why is it important?

a choose b counts the number of ways you can pick b things from a set of a things. For example $\binom{8}{2}=\frac{8!}{2!(8-2)!}