CP 3.1, CP 3.2

Matrix arithmetic, identity and zero

The lesson

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(3−124)\mathbf{A} = \begin{pmatrix} 3 & -1 \\ 2 & 4 \end{pmatrix} and B=(15−20)\mathbf{B} = \begin{pmatrix} 1 & 5 \\ -2 & 0 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(20−31)\mathbf{A} = \begin{pmatrix} 2 & 0 \\ -3 & 1 \end{pmatrix} and B=(4−213)\mathbf{B} = \begin{pmatrix} 4 & -2 \\ 1 & 3 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(1234)\mathbf{A} = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix} and B=(0110)\mathbf{B} = \begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(−251−1)\mathbf{A} = \begin{pmatrix} -2 & 5 \\ 1 & -1 \end{pmatrix} and B=(3122)\mathbf{B} = \begin{pmatrix} 3 & 1 \\ 2 & 2 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(102−131)\mathbf{A} = \begin{pmatrix} 1 & 0 & 2 \\ -1 & 3 & 1 \end{pmatrix} and B=(210−114)\mathbf{B} = \begin{pmatrix} 2 & 1 \\ 0 & -1 \\ 1 & 4 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(2−1011302−2)\mathbf{A} = \begin{pmatrix} 2 & -1 & 0 \\ 1 & 1 & 3 \\ 0 & 2 & -2 \end{pmatrix} and B=(14−1)\mathbf{B} = \begin{pmatrix} 1 \\ 4 \\ -1 \end{pmatrix}.
[3]

3 marksCore techniqueShow full working

Find AB\mathbf{A}\mathbf{B}, where A=(1−23)\mathbf{A} = \begin{pmatrix} 1 & -2 & 3 \end{pmatrix} and B=(20111003−1)\mathbf{B} = \begin{pmatrix} 2 & 0 & 1 \\ 1 & 1 & 0 \\ 0 & 3 & -1 \end{pmatrix}.
[3]

4 marksCore techniqueShow full working

A=(2k13)\mathbf{A} = \begin{pmatrix} 2 & k \\ 1 & 3 \end{pmatrix}.
(a)
Given that the top-left entry of A2\mathbf{A}^2 is 1010, find kk.
[2]
(b)
Hence find A2\mathbf{A}^2.
[2]

4 marksCore techniqueShow full working

A=(1k2−1)\mathbf{A} = \begin{pmatrix} 1 & k \\ 2 & -1 \end{pmatrix}.
(a)
Given that the top-left entry of A2\mathbf{A}^2 is 99, find kk.
[2]
(b)
Hence find A2\mathbf{A}^2.
[2]

4 marksCore techniqueShow full working

A=(3k−12)\mathbf{A} = \begin{pmatrix} 3 & k \\ -1 & 2 \end{pmatrix}.
(a)
Given that the top-left entry of A2\mathbf{A}^2 is 55, find kk.
[2]
(b)
Hence find A2\mathbf{A}^2.
[2]

4 marksCore techniqueShow full working

A=(2134)\mathbf{A} = \begin{pmatrix} 2 & 1 \\ 3 & 4 \end{pmatrix} and I\mathbf{I} is the 2×22 \times 2 identity matrix.
Find the constants pp and qq such that A2=pA+qI\mathbf{A}^2 = p\mathbf{A} + q\mathbf{I}.
[4]

4 marksCore techniqueShow full working

A=(12−13)\mathbf{A} = \begin{pmatrix} 1 & 2 \\ -1 & 3 \end{pmatrix} and I\mathbf{I} is the 2×22 \times 2 identity matrix.
Find the constants pp and qq such that A2=pA+qI\mathbf{A}^2 = p\mathbf{A} + q\mathbf{I}.
[4]

4 marksCore techniqueShow full working

A=(3−210)\mathbf{A} = \begin{pmatrix} 3 & -2 \\ 1 & 0 \end{pmatrix} and I\mathbf{I} is the 2×22 \times 2 identity matrix.
Find the constants pp and qq such that A2=pA+qI\mathbf{A}^2 = p\mathbf{A} + q\mathbf{I}.
[4]

Independent practice for Pearson Edexcel A-level Further Mathematics (9FM0), not endorsed by Pearson.

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