Question

Find the cosine and sine of 210. Round your answers to the nearest hundredth if necessary

Answer 1

The cosine is -0.88
This is rounded from -0.88387747318

The sine is .48.
This is rounded from 0.46771851834

Answer 2

`sin 210^(\circ)=-0.5`

`cos 210^(\circ)=-0.87`

Explanation:

We are given that

`sin210^(\circ)` and
`cosin 210^(\circ)`

We have to find the value of cosine and sine 210 degrees.

`sin 210^(\circ)= sin (\pi+30)= - sin 30^(\circ)` (
`\pi=180^(\circ), sin(\pi+\theta)=-sin\theta)`

`sin 210^(\circ)=-(1)/(2)=-0.5` ..... (
`sin 30^(\circ)=(1)/(2)`)

`cos 210^(\circ)=cos (\pi+30)`

`cos 210^(\circ)=-cos 30^(\circ)=-(\sqrt3)/(2)`

`cos 210^(\circ)=-0.87`

`cos (\pi+\theta)=-cos\theta`,
`cos30^(\circ)=(\sqrt3)/(2)`)

Hence, the value of

`sin 210^(\circ)=-0.5`

`cos 210^(\circ)=-0.87`