Determine which of the following sets of n × n matrices are subspaces of .a) The n × n dia...

Determine which of the following sets of n × n matrices are subspaces of .

a) The n × n diagonal matrices

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b) The n × n upper triangular matrices

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c) The n × n symmetric matrices

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d) The n × n matrices of determinant zero

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e) The n × n invertible matrices