InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
the value of `Sigma_(r=2)^(n) (-2)^(r )|{:( ""^(n-2)C_(r-2),,""^(n-2)C_(r-1),,""^(n-2)C_(r)),(-3,,1 ,,1),(2,,-1,,0):}| (n gt 2)`A. `2n -1+(-1)^(n)`B. `2n+1+(-1)^(n-1)`C. `2n-3+(-1)^(n)`D. none of these |
|
Answer» Correct Answer - A Applying `c_(1) to C_(1) +2C_(2)+C_(3)` we get `S=overset(n)underset(r=2)(Sigma)(-2)^(r ) |{:(.^(n)C_(r),,.^(n-2)C_(r-1),,.^(n-2)C_(r )),(0,,1,,1),(0,,-1,,0):}|` `=overset(n)underset(r=2)(Sigma) (-2)^(rn)C_(r ) =overset(n)underset(r=0)(Sigma) (-2)^(r " " n)C_(r )-(.^(n)C_(0)-2.^(n)C_(1))` `=(1-2)^(n)-(1-2n) =2n-1+(-1)^(n)` |
|