- #1
roam
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(a) Let [tex]A = \left(\begin{array}{ccc}1\\2\\-2\end{array}\right)[/tex], B = (0 3 -1)
Find AB and BA or else explain why it cannot be done.
(b) Let [tex]R_{\theta} = \left(\begin{array}{ccc}cos\theta&-sin\theta\\sin\theta&cos\theta\end{array}\right)[/tex], Find [tex]R_{\theta}R_{-\theta}.[/tex]
The Attempt at a Solution
(a) I believe that AB & BA cannot be computed because one of them is a row while the other one is a column. A column represents a vector whilst a row represents a point.
The only way to find AB is to find B transpose aka BT and hence compute ABT.
Is this the right answer for part (a) ? Thanks.