AQA
Further AS Paper 1
2020
June
Q6
2 marks
Standard +0.3
Anna has been asked to describe the transformation given by the matrix
$$\begin{bmatrix} 1 & 0 & 0 \\ 0 & -\frac{\sqrt{3}}{2} & -\frac{1}{2} \\ 0 & \frac{1}{2} & -\frac{\sqrt{3}}{2} \end{bmatrix}$$
She writes her answer as follows:
The transformation is a rotation about the \(x\)-axis through an angle of \(\theta\), where
$$\sin \theta = \frac{1}{2} \quad \text{and} \quad -\sin \theta = -\frac{1}{2}$$
$$\theta = 30°$$
Identify and correct the error in Anna's work.
[2 marks]