Question

sec (-60)
The answerr is 1 right?

Answer 1

sec(-60) = 1/(cos(-60))

sec(-60) = 1/(cos(60)) ... because cosine is an even function

sec(-60) = ???

Answer 2

well, what does your unit circle tell you? :)

Answer 3

So, following what @jim_thompson5910 said above,

what is cos 60?

Answer 4

cos=\[\frac{ adj }{ hyp }=\sqrt{3}\]

Answer 5

http://i.stack.imgur.com/r8uHr.gif

Answer 6

Cos 60 = 1/2

So, sec 60 = 1/cos 60 = 2

Answer 7

this is same as sec(-60)

Answer 8

so 60\[\sec (-60) = 1/\cos (-60) =\sqrt{3}
Then 60 degree on the unit circle is \[\frac{ \pi }{ 3}\]
which equals \[\left[\begin{matrix}1 & 2 \\ \sqrt{3} & 2\end{matrix}\right]\]
Snices we know cos is \[\sqrt{3}\] we want the bottom number which is 2