Graphs of the Sine and Cosine Functions

Properties of functions can be observed from their graphs. We begin by graphing the sine and the cosine functions. We make a table of values, plot the points, and then connect those points with a smooth curve. It is helpful to first draw a unit circle and label a few points with coordinates. We can either use the coordinates as the function values or find approximate sine and cosine values directly with a calculator.

s sin s cos s
0 0 1
π/6 0.5 0.8660
π/4 0.7071 0.7071
π/3 0.8660 0.5
π/2 1 0
3π/4 0.7071 -0.7071
π 0 -1
5π/4 -0.7071 -0.7071

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