(a) Simplify (n/k)/(n/(k - 1))
(b) For some positive integer n, the expansion of (1 + x)^n has three consecutive coefficients a, b, c that satisfy 1:8:28. What must n be?
b)
Suppose the coefficients are: (n / r−1), (n / r), (n / r+1).
Then [n−r+1] / r =8 : 1, [n−r] / [r+1] =28 : 8, solve for n, r
n ==8 and r ==1 Expand (x + 1)^8 ==x^8 + 8 x^7 + 28 x^6 + 56 x^5 + 70 x^4 + 56 x^3 + 28 x^2 + 8 x + 1
So, the first 3 coefficients are: 1 : 8 : 28
