Solution
Related Formula
Tᵣ₊₁ = nr an-r b^rCore Logic
The general term in the expansion is:
Tᵣ₊₁ = nr (7)(n-r)/(3) (11)(r)/(12)For the term to be integral, both powers (n-r)/(3) and (r)/(12) must be integers. This dictates that r must be a multiple of 12 (r = 12k, where k is a non-negative integer).
Step 1: Setup total count equation
The values r can take are 0, 12, 24, , 12k. The total number of terms is given as 183. Since counting starts from k=0, the maximum value of k is:
k = 183 - 1 = 182Step 2: Calculate minimum n
The maximum index value r required to achieve this count is:
r = 12 × 182 = 2184Hence, the least value of n must be 2184 to encompass all 183 integral terms.
Pattern Recognition
Number of terms formula when tracking steps of size L: Total Terms = (n)/(L) + 1. Isolate n directly to compute bounds rapidly.
Chapter Mix
Class 11 Mathematics: Binomial Theorem