Rotate $$$\left(2 \sqrt{2}, - \frac{\sqrt{2}}{4}\right)$$$ by $$$45^{\circ}$$$ counterclockwise around $$$\left(0, 0\right)$$$
Your Input
Rotate $$$\left(2 \sqrt{2}, - \frac{\sqrt{2}}{4}\right)$$$ by the angle $$$45^{\circ}$$$ counterclockwise around $$$\left(0, 0\right)$$$.
Solution
Rotation of a point $$$\left(x, y\right)$$$ around the origin by the angle $$$\theta$$$ counterclockwise will give a new point $$$\left(x \cos{\left(\theta \right)} - y \sin{\left(\theta \right)}, x \sin{\left(\theta \right)} + y \cos{\left(\theta \right)}\right)$$$.
In our case, $$$x = 2 \sqrt{2}$$$, $$$y = - \frac{\sqrt{2}}{4}$$$, and $$$\theta = 45^{\circ}$$$.
Therefore, the new point is $$$\left(2 \sqrt{2} \cos{\left(45^{\circ} \right)} - - \frac{\sqrt{2}}{4} \sin{\left(45^{\circ} \right)}, 2 \sqrt{2} \sin{\left(45^{\circ} \right)} + - \frac{\sqrt{2}}{4} \cos{\left(45^{\circ} \right)}\right) = \left(\frac{9}{4}, \frac{7}{4}\right).$$$
Answer
The new point is $$$\left(\frac{9}{4}, \frac{7}{4}\right) = \left(2.25, 1.75\right)$$$A.