Unit Circle You will use the Unit Circle for nearly every computation for the rest of Trig. Make the most of today… Memorize the angles and Radians Memorize the sine and cosine values Look for Patterns and use them!

Unit Circle being one unit in radius. The Unit Circle is called “Unit” Circle because we define it as being one unit in radius. This helps with formulas and finding values. It helps me to think of the unit circle as being cut into sections. The distance around the circle is

Cut the circle into halves. Add the sine and cosine values. Use ordered pairs (cos, sin) Add the Degrees Remember: Radius = 1 unit!!

Unit Circle We will add radians, degrees, and trig values to each other line on the circle. Write neatly and stay organized. Watch the distances on the x and y axis to help you with (cos, sin)

Distances on the axis

Now add the Count by 1/4ths

Add the degrees 0°, 360° 90° 180° 270° 135° 225° 315° 45° Notice: as you go around the circle, you are adding 45 to the last number to get the next number each time

Figure (Cos, Sin)

Now add the Count by 1/6ths Just write down the simplified form—I am counting them out for you so you see the pattern

90° 180° 270° Add the Degrees 0°, 360° 30° 60° 120° 150° 210° 240° Notice: as you go around the circle, you are adding 45 to the last number to get the next number each time 300° 330°

Figure (Cos, Sin)

Practice and Memorize! A good way to practice in pairs is to quiz each other…”What is the sin of 90 degrees?” A good way to practice by yourself is to draw a circle and fill in parts. Don’t waste this time! Practice!

Try these before practicing on your own. Cos of ¶/4 Sin of ¶/3 Cos of 5 ¶/3 What is 90 degrees in radians? Cos of ¶ Sin of 2 ¶

That’s It Get to work…use your time wisely!