The circle with a radius of one unit is partitioned into twelve equal arcs, where each arc corresponds to specific $t$-values. Determine the value of the trigonometric function at the given real number $t$ using the $\left(x,y\right)$ coordinates in the diagram or specify that the expression is undefined.

$\tan\frac{\pi}{2}$

• A. $1$
• B. $0$
• C. $\frac12$
• D. Undefined

Answer: (D)