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Section 4.3 The Unit Circle. Quadrantal Angles. π 2. , 90˚. (0, 1). A. S. 0, 0˚ 2 π , 360˚. π , 180˚. (-1, 0). (1, 0). T. C. (0, -1). 3π 2. , 270˚. “ A ll S tudents T ake C alculus” tells you where each trig function is positive. Let’s begin with an easy family….
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Quadrantal Angles π 2 , 90˚ (0, 1) A S 0, 0˚ 2π, 360˚ π, 180˚ (-1, 0) (1, 0) T C (0, -1) 3π 2 , 270˚ “All Students Take Calculus” tells you where each trig function is positive.
Let’s begin with an easy family… What are the coordinates? Now, reflect the triangle to the second quadrant…
What are the coordinates? Now, reflect the triangle to the third quadrant…
What are the coordinates? Now, reflect the triangle to the fourth quadrant…
**REMEMBER!!! cosθis represented by the x-coordinates and sin θis represented by the y-coordinates.** EX. Evaluate the six trig functions at θ = .
EX. Evaluate the six trig functions at θ= . Homework: worksheet
Complete the family… Now, reflect the triangle to the second quadrant.
What are the coordinates? Now, reflect the triangle to the fourth quadrant.
EX. Evaluate the six trig functions at θ = . Homework: worksheet
Complete the family… 60˚ Now, reflect the triangle to the second quadrant.
What are the coordinates? Now, reflect the triangle to the third quadrant.
What are the coordinates? Now, reflect the triangle to the fourth quadrant.
Shortcut to remember ordered pairs in quadrant 1 • Parenthesis • Fractions with denominator of 2 • 3) • 4) Square roots 13 22 31
EX. Evaluate the six trig functions at θ = . Homework: worksheet