

InterviewSolution
Saved Bookmarks
1. |
If Z is an idempotent matrix, then `(I+Z)^(n)`A. `I+2^(n)Z`B. `I+(2^(n)-1) Z`C. `I-(2^(n)-1)Z`D. none of these |
Answer» Correct Answer - B Z is idempotent, then `Z^(2)=Zimplies Z^(3), Z^(4), ..., Z^(n)=Z` `:. (I+Z)^(n)=^(n)C_(0)I^(n)+ .^(n)C_(1)I^(n-1) Z+.^(n)C_(2)I^(n-2)Z^(2)+ +^(n)C_(n)Z^(n)` `=^(n)C_(0)I+ .^(n)C_(1)Z+ .^(n)C_(2)Z+ .^(n)C_(3)Z+ +^(n) C_(n)Z` `=I +(.^(n)C_(1)+.^(n)C_(2)+.^(n)C_(3)+ +.^(n)C_(n))Z` `=I+(2^(n)-1)Z` |
|