Answer:
Step-by-step explanation:
Given that A is a square matrix and A is idempotent

Consider I-A
i) 
It follows that I-A is also idempotent
ii) Consider the matrix 2A-I

So it follows that 2A-I matrix is its own inverse.
 
        
             
        
        
        
Answer:
how many numbers have absolute value 3? zero is your answer 
how many numbers have absolute value a, if a>0? your answer is also zero
Step-by-step explanation:
 
        
             
        
        
        
Answer: The perimeter of a square is defined as the length that its boundary covers. The formula to calculate the perimeter of a square is given as: P = 4 × side.
Step-by-step explanation: