Question

How to find the value of x where `0<=x<=360^@` for `sec x= 3.1909`?

Answer 1

`sec x = 1/cos x = 3.1909 -> cos x = 1/3.1909 = 0.31`

`cos x = 0.31 -> x = +- 71.94 deg`

Within period (0, 2pi):

x = 71.94 deg
x = 360 - 71.94 = 288.06 deg