Question

find the value of cos 930°​

Answer 1

Answer:

This can be written as

cos (900+30)

Now this expression lies in third quadrant,

Therefore it becomes

-cos30

-sqrt3/2 (answer)

Answer 2

The value of $\cos 930$ = $-\dfrac{\sqrt{3}}{2}$

Step-by-step explanation:

We have,

$\cos 930$

To find, the value of $\cos 930$ = ?

∴ $\cos 930$

= $\cos (3\pi-150)$

Using the trigonometric identity,

$\cos (3\pi-A)=\cos A$

$= \cos 150$

$= \cos (180-30)$

Using the trigonometric identity,

$\cos (180-A)=-\cos A$

$= -\cos 30$

= $-\dfrac{\sqrt{3}}{2}$ [ ∵ $\cos 30=\dfrac{\sqrt{3}}{2}$]

∴ The value of $\cos 930$ = $-\dfrac{\sqrt{3}}{2}$