The (-12,-5) indicates the following.
[tex](-12,-5)=(x,y)[/tex]
To determine the value of r, we solve as follows.
[tex]\begin{gathered} r=\sqrt[]{x^2+y^2} \\ r=\sqrt[]{(-12)^2+(-5)^2} \\ =\sqrt[]{144+25} \\ =\sqrt[]{169} \\ =13 \end{gathered}[/tex]
To find the value of secθ, we substitute as follows.
[tex]\sec \theta=\frac{r}{x}=\frac{13}{-12}=-\frac{13}{12}[/tex]
