Question

Binomial theorem - can anyone help me understand this? (pic attached)

What are the things in parenthesis and how do they result in 1, 4, 6, 4 and 1? I can understand the rest, just not that part.

Answer 1

ok its rule of combination

Answer 2

the rule is \[c _{r}^{n}=\frac{ n! }{ r!(n-r)! }\]

Answer 3

r u following me

Answer 4

yep. got it now. ty

Answer 5

\[\left(\begin{matrix}4 \\ 1\end{matrix}\right)=c _{1}^{4}=\frac{ 4! }{ 1!(4-1)! }\]

Answer 6

medal?