Trigonometry – Unit Circle construction from scratch

By | October 5, 2016

Unit Circle construction from scratch

In this tutorial students learn how to create the Unit Circle based on knowledge of the 30,60,90 and 45,45,90 special triangle and fact that x=cos(theta) and y=sin(theta).

Virginia Standards of Learning (SOL) T.1, T.2, T.3

Notice how all of the (x,y) values have a denominator of 2.

Notice the 1, 2, and 3 counting technique used for each of the numerators.

Take the square root of each numerator.

Make note of the quadrant that the point appear in to ensure the usage of proper signs.

Quadrant I (+,+)
Quadrant II (-,+)
Quadrant III (-,-)
Quadrant IV (+,-)

Make your way around the Unit Circle by just counting by 3rds (1/3) and 4ths (1/4).

** Simplify those fractions when necessary.