Question

How do you evaluate sin(-3π/2)?

Answer 1

`sin(-(3pi)/2) = 1`

Explanation:

As an angle `-(3pi)/2` is equivalent to `pi/2`

`-(3pi)/2` is `3/4` of a circle in a clockwise direction.
`pi/2` is `1/4` of a circle in a counter clockwise direction.

`sin(pi/2) =1`

If you think in terms of a unit radius circular segment centered on the origin of the Cartesian plane with its base along the positive X-axis, then the inscribed right-angled triangle at `pi/2` will have a vertex on the positive Y-axis and both the hypotenuse and opposite side will have a length of `1`