5.2 The sine and cosine curves

Handout: Lesson 2 The Sine and Cosine Curves

Handout solution:

The values of sine found on the calculator are measurements on the unit circle below.

The value of sine is the length of the green half chord on the circle below. To be more precise, the value sine is the y coordinate of the point on the circumference of the circle. It takes positive and negative values, depending on the quadrant.

Likewise the value cosine is the x coordinate of the point on the circumference, which is the length of the red line segment – taking positive and negative values according to the quadrant.

The value tangent is the length of the blue line segment measured above (positive) or below (negative) the x axis. Unlike sine and cosine, tangent can take all real values.

Matching, 0 – 360

By consulting or visualizing the applet above, match the labels with their values.