Question

Evaluate sec960°.
1. -2
2. - 2 sqrt3/3
3. 2sqrt 3/3
4. 2

Answer 1

Answer:

-2

Step-by-step explanation:

We want to evaluate;

$\sec960\degree$

We use the reciprocals of trigonometric ratios to obtain;

$\sec960\degree=\frac{1}{\cos960\degree}$

The 960 degree angle makes an angle of 60 degree with the positive direction of the x-axis and it is in the 3rd quadrant.

This implies that;

$\sec960\degree=\frac{1}{-\cos60\degree}$

We use special trigonometric ratios to obtain;

$\sec960\degree=\frac{1}{-\frac{1}{2}}$

$\sec960\degree=-2$

Answer 2

Answer:

Option 1. ( -2)

Step-by-step explanation:

sec (960°)

= sec [ 360 × 2 + 180 + 60° ]

This signifies when we draw 960° it revolves 360° twice 180° once then 60° in third quadrant in positive direction.

That means sec 960 = -(sec60)

                                   = $-(\frac{1}{cos60})$

                                   = $\frac{-1}{\frac{1}{2} }$

                                   = (-2)

Option 1. ( -2) is the answer.