The Unit Circle & Trig Ratios B. Afghani Algebra PP2.ppt The Unit Circle & Trig Ratios LBUSD Math Office, 2002
Today’s Learning Questions: How do I create a unit circle? What are the “special angles” and how do I graph their arcs & triangles? How do I derive the side lengths for isosceles triangles whose hypotenuse = 1?
Today’s Learning Questions: How do I derive the side lengths for 30- 60-90 triangles whose hypotenuse = 1? What 5 values and their opposites are the sine and cosine values for each special angle between 0° and 360°? How may I use the unit circle graph to find the sine of a special angle? The cosine of an angle?
Today’s Learning Bonus Question: Why is the ratio of sine θ to cosine θ called tangent θ?
Angles Mathematicians Like Solve for a. 45° 1 a 45° a
Angles Mathematicians Like Solve for a. a 1 1 b 60° a a 60° 1
Angles Mathematicians Like Solve for b. a 1 1 b 60° a a 60° 1
Put in order from least to greatest:
Please label these items on your coordinate grid: The origin The x-axis The y-axis
What makes a circle a “unit circle”? y-axis r = 1 (0, 0) the origin What makes a circle a “unit circle”? x-axis
(0, 1) What are the coordinates for the graphed points? y (1, 0) (-1, 0) x (0, -1)
y 1 y x x
Trigonometric Ratios
90° y 90° 120° 60° 45° 135° 150° 45° 30° a 1 0°, 360° 0°, 360° 180° 180° 0° 0° 45° x 210° 330° 225° 315° 240° 270° 270° 300°
y 0, x
90° y 90° 120° 60° 45° 135° 150° 45° 30° a 1 0°, 360° 0°, 360° 180° 180° 0° 0° 45° x 210° 330° 225° 315° 240° 270° 270° 300°
Trig Ratios
y 90° 120° 60° 150° 30° 180° 0°, 360° 0° x 210° 330° 240° 270° 300°
y 0, x
Trig Ratios 60° 300°
Today’s Learning Questions: How do I create a unit circle? What are the “special angles” and how do I graph their arcs & triangles? How do I derive the side lengths for isosceles triangles whose hypotenuse = 1?
Today’s Learning Questions: How do I derive the side lengths for 30- 60-90 triangles whose hypotenuse = 1? What 5 values and their opposites are the sine and cosine values for each special angle between 0° and 360°? How may I use the unit circle graph to find the sine of a special angle? The cosine of an angle?
Today’s Learning Bonus Question: Why is the ratio of sine θ to cosine θ called tangent θ?
Bonus Question