CAPE Pure Mathematics Unit 2 · May/June 2015 · Paper 1 · Question Q38
If P = \begin{pmatrix} 1 & -2 & 0 \\ 3 & 1 & 5 \\ -1 & 2 & 3 \end{pmatrix} and Q = \begin{pmatrix} -7 & 6 & -10 \\ -14 & 3 & -5 \\ 7 & 0 & 7 \end{pmatrix} then PQ = \begin{pmatrix} 21 & 0 & 0 \\ 0 & 21 & 0 \\ 0 & 0 & 21 \end{pmatrix}.
The matrix P^{-1} equals
- (A)
(PQ)^{-1} - (B)
(QP)^{-1} - (C)
\frac{1}{21}P - (D)
\frac{1}{21}Q
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