# Christmas Blast!!!

**Algebra**Level 5

If

\(\displaystyle X_r = \begin{pmatrix} cos\left(\dfrac{\pi}{2^{r}} \right) & sin\left(\dfrac{\pi}{2^{r}} \right) \\ -sin\left(\dfrac{\pi}{2^{r}} \right) & cos\left( \dfrac{\pi}{2^{r}} \right) \end{pmatrix}\)

And

\(\displaystyle K = \lim_{r \to \infty } X_1.X_2.X_3 \ldots X_r\)

Then find \(100K\).

**Clarification**

\(X_r\) is a \(2 \times 2\) ordered matrix

K(matrix) can be represented as a real number

# Merry Christmas to all

This question is flagged because it is not clear how "A matrix can be represented as a real number".