Two. A point $P(x, y)$ on the unit circle $x^2 + y^2 = 1$ has $x$-coordinate $\frac{5}{13}$. The $y$-coordinate is negative. If $s$ is a real number such that the arclength along the unit circle from $(1, 0)$ to $P$ is $s$ units, find the following:
A. $\sin s$
B. $\tan s$
C. $\cos^2 s + \sin^2 s$