Explain how the unit circle relates the cosine and sine of an angle to the coordinates of a point on the circle.

The x-coordinate of the point is the cosine of the angle, and the y-coordinate of the point is the sine of the angle.

Describe the pattern of sine values for the angles 0, π/6, π/4, π/3, and π/2 using the 'root over two' method.

The sine values are √0/2, √1/2, √2/2, √3/2, and √4/2.

Grade 11th Grade · 45 min

I can convert between degree and radian measures for angles in the first quadrant and determine the sine and cosine.

Professor Dave Explains · 9:48

The Easiest Way to Memorize the Trigonometric Unit Circle

3 key concepts

1
The unit circle is a circle with a radius of one superimposed on the coordinate plane, with its center at the origin.
2
Every point on the unit circle has an X coordinate equal to cosine θ and a Y coordinate equal to sine θ.
3
The sine values for angles in the first quadrant start at the X axis with a value of √0/2, then climb to √1/2, √2/2, √3/2, and finally √4/2 at the Y axis.

8 questions · Multiple choice & Short answer

Quick comprehension check

“An angle measures π/3 radians. What is its measure in degrees? Also, what are the sine and cosine of this angle?”

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