Question

How do you evaluate `sec 780`?

Answer 1

2

Explanation:

`sec (780) = 1/(cos 780).`
Find cos (780).
`cos (780) = cos (60 + 2(360)) = cos 60`
Trig table gives:
`cos 60 = 1/2`.
There for:
`sec 780 = 1/(cos 60) = 2`