Question 459727
Refer to the unit circle. When you plot 2pi/3, you will see that the y-coordinate is sqrt(3)/2 and the x-coordinate is -1/2. These correspond to sine and cosine, respectively, so we have sin(2pi/3) = sqrt(3)/2 and cos(2pi/3) = -1/2. That's all you need for parts a and b.


Try c) using the same method. Of course you will have to find both x- and y- coordinates to evaluate tangent, but you can still use the 30-60-90 triangle. And for the last question you will need a calculator.