Question

What is the sine, cosine, & tangent of 270 degrees?

Answer 1

`sin(270^o) = -1, cos (270^0) = 0, tan (270^0)=` undefined.

Explanation:

Consider the unit circle (a circle with radius 1). On the unit circle as graphed on an xy coordinate plane, with 0 degrees starting at (x,y) = (1,0):

graph{x^2+y^2=1 [-1, 1, -1, 1]}

If we draw a line from the origin at the angle we seek, then where that line intersects the unit circle, the sin of the angle will be equal to the y-coordinate, and the cosine will be equal to the x-coordinate, with the tangent being equal to the sine divided by the cosine. If this is the case, then at 90 degrees, we will intersect the unit circle at the point (0,1), and at 270 degrees we will be at `(0,-1)`.

Given that, we can easily find the sine and cosine:

`sin(270^o) = -1, cos(270^o) = 0, tan(270^o) = -1/0 =` undefined.