Question

How do I find the value of sec 5pi / 6?

Answer 1

`color(blue)(-(2sqrt(3))/3`

Explanation:

`sec((5pi)/6)`

Identity:

`color(red)bb(sec(x)=1/cos(x))`

`cos((5pi)/6)=-cos(pi-(5pi)/6)=-cos(pi/6)=-sqrt(3)/2`

`sec((5pi)/6)=1/-cos((pi)/6)=1/((-sqrt(3))/2)=color(blue)(-(2sqrt(3))/3`