Question

How could you explain the sine and cosine relationships to someone who doesn't know about the unit circle? What visuals could you use to help explain the idea of how these two measures are related?

Answer 1

If you have a unit circle, it means that you have a circle of radius r = 1 unit. So if we consider the scalene triangle of the figure, its vertical side is the sine of the theta angle and its horizontal side is the cosine of the theta angle. Then to find the hypotenuse of the triangle you use the Pythagorean theorem, thus relating the sine and cosine measures. I attach the solution.