Science:Math Exam Resources/Courses/MATH307/December 2010/Question 01 (b)
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Question 01 (b) 

Let where a is a real number. (b) For what values of a (if any) is cond(A) not defined? Give a reason. 
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Hint 

Recall that . For which values of a is A not invertible? 
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Solution 

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Please rate my easiness! It's quick and helps everyone guide their studies. Please refer to part (a) regarding the computation of Recall that
With A being a diagonal matrix, its inverse is given by:
valid for all values where a is nonzero. When a is zero, this inverse, and hence cond(A) is undefined. Similar to , we have and these are defined for all nonzer values of a. So cond(A) is defined for all values of a, except a = 0. 