Find the exact value of the trigonometric function at the given real number?
- Sin (21pi/2)
- Cos (21pi/2)
- Cot (21pi/2)

Question

anonymous · Answer

$$\sin(21\pi /2 ) = (21\pi/2 )(180/\pi) = \sin(1890) = 1$$$$\cos(21\pi / 2) = (21\pi/2)(180/\pi) = \cos(1890) = 0$$$$\cot(1890) = 1/\tan(1890) =\cos(1890)/\sin(1890) = 0$$

All you have to do is convert the angle from radians to degree by multiplying the given angle with:

$$180/\pi$$

but if you want to convert from degree to radians then multiply by:

$$\pi/180$$

^_^