Answer
0
Work Step by Step
To find out the value of $ \cot 90^{\circ}$-
We will draw $90^{\circ}$ in standard position, locate point (0.1) on the terminal side and use Definition I-
Using the point (0,1)
x = 0, y = 1 and r = 1
$\cot 90^{\circ} = \frac{x}{y}$
$\cot 90^{\circ} = \frac{0}{1}$
$\cot 90^{\circ}$ = 0
