Question

What is the value of sec(-30°)?

Answer 1

`(2.√(3) )/(3)`

Explanation:

Sec = 1/cos

Using the above identity, we can write the given sec(-30) as

sec(-30) = 1/ cos(-30)

On the trigonometric unit circle.

cos(-30) = cos(30) =
`(√(3) )/(2)`

Therefore,

sec(-30) = 1/cos(-30) = 1/cos(30)

Now plug in cos(30) = √3/2

sec(-30) = 1/ (√3/2)

= 1 * 2/√3

= 2/√3

Since we have radical number in the denominator, so we can multiply both the numerator and the denominator by √3.

= (2*√3) /(√3*√3)

= 2√3 /3

Answer:
`(2.√(3) )/(3)`

Hope you will understand the concept.

Thank you.