Question

Find sec $\theta$, if $\theta$ be an angle in standard position with (x, y) a point on the terminal side of $\theta$ and r = $\sqrt{x^2+y^2}\ne 0$.

• A. $\frac{y}{r}$
• B. $\frac{r}{y}$
• C. $\frac{x}{r}$
• D. $\frac{r}{x}$

Answer 1

The correct option is D $\frac{r}{x}$

By using Pythagoras theorem, we will find the value of hypotenuse.
$x^2+y^2=r^2$

So, sec $\theta$ = $\frac{hypotenuse}{adjacentside}$= $\frac{r}{x}$

sec $\theta$ = $\frac{r}{x}$

So, option D is correct.