### Home > PC > Chapter 6 > Lesson 6.3.1 > Problem6-114

6-114.

Find the exact value of $\sec \left(a + b\right)$ where $\cos a = \frac { 3 } { 5 }$, $\tan b = −\frac { 12 } { 5 }$, $\sin a \gt 0$ and $\csc b \lt 0$. Hint: Find $\cos\left(a + b\right)$.

Sketch two triangles for this situation. One for angle $a$ and one for angle $b$.