Answer
1
Work Step by Step
To find out the value of $ \sec 0^{\circ}$-
We will consider $90^{\circ}$ in a position such that y=0. locate point (1.0) on the terminal side and use Definition I-
Using the point (1,0)
x = 1, y = 0 and r = 1
$\sec 0^{\circ} = \frac{r}{x}$
$\sec 0^{\circ} = \frac{1}{1}$
$\sec 0^{\circ}$ = 1
