The unit circle is an underused tool for figuring out which exact values go with which special angle (30, 45, 60, 90, 120, 135, ... or pi/6, pi/4, pi/3, pi/2, 2pi/3, 3pi/4, ...). Using the definitions of cos as the x-coordinate, sine as the y-coordinate, and tan as the slope, this becomes much easier since the values of sin, cos, and tan can be estimated visually. As usual, understanding is better than brute force memorisation.
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26 авг 2024