

InterviewSolution
Saved Bookmarks
1. |
Let `f(n)= (k=1)Σ^n k^2(n C_k)^ 2` then the value of f(5) equalsA. `1000`B. `1250`C. `1750`D. `2500` |
Answer» Correct Answer - C `(c )` `k^(n)C_(k)=n^(n-1)C_(k-1)` `:.sum_(k=1)^(n)k^(2)("^(n)C_(k))^(2)` `=n^(2)sum_(k=1)^(n)("^(n-1)C_(k-1))^(2)` `=n^(2)("^(2n-2)C_(n-1))` `:. F(5)=25("^(8)C_(4))=1750` |
|