Question

what does the following symbol stand for

Answer 1

is it alway

Answer 2

combination

\[^{n} C_{k}\]

Answer 3

****Does it always stand for a combination ?

Answer 4

it is the binomial coefficient\[\binom nk=\frac{n!}{k!(n-k)!}\]

Answer 5

thanks @TuringTest

Answer 6

yes... important in binomial theory ...

Answer 7

if you wanted to expand \[(x+y)^n\]you could write\[(x+y)^n=\sum_{k=0}^n\binom nkx^{n-k}y^k\]it comes up all over the place
probability in particular

Answer 8

Make sure you don't confuse it with \[\left(\frac{a}{n}\right)\]Which is a similar looking symbol, that is entirely unrelated.

Answer 9

^what the heck does that mean?

Answer 10

The above is the Jacobi symbol! Which is the same as this symbol: \[\left(\frac{a}{p}\right)\]when n is prime.

Answer 11

And that last symbol was the Legendre symbol. In case you were wondering.

Answer 12

I'll be looking that up
thanks KG