Easy Practice — Set 2

Quick Recap — Coefficients & Middle Terms

• Middle term: for even $n$, the $\big(\tfrac n2+1\big)$th term; for odd $n$, two middle terms.
• Sum of coefficients of a polynomial $=$ its value at $x=1$.
• The greatest binomial coefficient in $(1+x)^n$ is the central one, $^nC_{n/2}$ (or $^nC_{(n\pm1)/2}$).
• Coefficients equidistant from the ends are equal: $^nC_r={}^nC_{n-r}$.