Question

Which expression is equivalent to sin7pi/6?

A. sinpi/6
B. sin5pi/6
C. sin5pi/3
D. sin11pi/6

Answer 1

The answer choice is D because sin7pi/6 which it’s exact form is -1/2 the only answer choice which the same exact form is D.

Answer 2

For this case we must find an expression equivalent to:

`Sin (\frac {7 \pi} {6})`

According to the unit circle,
`\frac {7 \pi} {6}` is in the third quadrant and equals 210 degrees.

Then, we must find an expression equivalent to:

`Sin (210) = - \frac {1} {2} = - 0.5`

We have to:

`\frac{11 \pi} {6}`

It is in the fourth quadrant and is equivalent to 330 degrees, according to the unit circle.

`Sin (330) = - \frac {1} {2} = - 0.5`

Answer:

Option D