Question:
Mark the tick against the correct answer in the following:
$\left|\begin{array}{cc}\cos 70^{\circ} & \sin 20^{\circ} \\ \sin 70^{\circ} & \cos 20^{\circ}\end{array}\right|=?$
A. 1
B. 0
C. $\cos 50^{\circ}$
D. $\sin 50^{\circ}$
Solution:
