Question

What are the sine, cosine, and tangent of -pi/4? AND how did you get the answers?

Answer 1

Calculator in radians

Answer 2

Alternatively, you can convert the radians to degrees, and then use your calculator from there. There are 2pi radians in a circle, and 360 degrees in a circle. So pi radians = 180 degrees. Thus, -pi/4 radians = -180/4 degrees, or -45 degrees.