Chapter 3 - Radian Measure and the Unit Circle - Section 3.3 The Unit Circle and Circular Functions - 3.3 Exercises - Page 117: 31

$-1.0460$

Step 1: sec$(2.8440)$ is equal to the reciprocal of $cos (2.8440)$. Step 2: Convert the calculator to radian mode. Step 3: Type $\frac{1}{cos (2.8440)}$ into the calculator and press enter. Step 4: $\frac{1}{cos (2.8440)}\approx-1.0460$