Question 9
Rotate $P=(4,7)$ counterclockwise about the origin through $\theta=90^\circ$. Use $x^{\prime}=x\cos\theta-y\sin\theta$, $y^{\prime}=x\sin\theta+y\cos\theta$. Find the new coordinates. Source clarification: the printed matrix has lost its row and column layout; these are the standard equations for the stated counterclockwise rotation.
