The secant function, abbreviated sec, is called a reciprocal function because it uses the reciprocal of the trig function, cosine. The secant function uses the ratio
![image0.png](https://www.dummies.com/wp-content/uploads/275303.image0.png)
Just as with the cosecant, the ratio of the sides is greater than 1.
![A right triangle with sides 5, 12, and 13.](https://www.dummies.com/wp-content/uploads/275304.image1.jpg)
A right triangle with sides 5, 12, and 13.
Using the triangle in the above figure, the two secants are
![image2.png](https://www.dummies.com/wp-content/uploads/275305.image2.png)