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1.3. Right Triangle Trigonometry. Unit Circle Definitions of the 6 Trig. Functions…. sin = y. cos = x. y x. 1 x. x y. 1 y. tan =. csc =. sec =. cot =. Non-Unit Circle Definitions of the 6 Trig. Functions…. y r. sin =. x r. cos =. y x. r x. x y. r y. tan =.
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1.3 Right Triangle Trigonometry
Unit Circle Definitions of the 6 Trig. Functions… sin = y cos = x y x 1 x x y 1 y tan = csc = sec = cot =
Non-Unit Circle Definitions of the 6 Trig. Functions… y r sin = x r cos = y x r x x y r y tan = csc = sec = cot =
These definitions are closely related to the unit circle definition. In the unit circle, the radius is = to 1, thereby eliminating the denominator. y r sin = x r cos =
Since this is a unit circle (radius of one), sin 45 = 2/2 (0,1) (2, 2) (2/2, 2/2) Now, on this second circle, the radius is no longer 1 unit (it’s 2). Therefore, sin 45 = y/r or sin 45 = 2/2 (2,0) (-1,0) (1,0) 45 (0,-1)
Let’s practice these definitions. Find exact values of the six trig. functions of the angle shown in the figure. = = = = = = 12 5 13 12 13 5 5 13 12 13 5 12 If this triangle was placed at the center of a circle, what would the radius of that circle be? sin = cos = tan = cos = cot = csc = y x r y x r r x x y y r (12,5) 13 5 a2 +b2 = c2 12 122 +52 = c2 169 = c2 13 = c
Your Turn #1: Place your work in your notebook. Find exact values of the six trig. functions of the angle shown in the figure. 5 5 Look back at the previous slide if you need assistance.
Your Turn #2: Place your work in your notebook. Find exact values of the six trig. functions of the angle shown in the figure. 4 8 Hint: Be sure to reduce radicals.
Let’s practice some more… Sketch a right triangle corresponding to the trig. function of the acute angle . Then determine the other five trig. functions of . = = = = = = 25 5 35 5 y r 3 2 5 3 5 2 tan = sec = csc = cos = cot = y x r x x y x r r y (5,2) 3 sin = 2 3 2 5 a2 + b2 = c2 a2 + 22 = 32 a2 + 4 = 9 a2 = 5 a = 5
Your Turn #3: Place your work in your notebook. Sketch a right triangle corresponding to the trig. function of the acute angle . Then determine the other five trig. functions of . Think sec = 4/1 sec = 4 Look back at the previous slide if you need assistance.
Your Turn #4: Place your work in your notebook. Sketch a right triangle corresponding to the trig. function of the acute angle . Then determine the other five trig. functions of . csc = 9 5 Look back if you need assistance.
What is SOH CAH TOA? This is another way of remembering the definitions of the trigonometric functions. SOH sin = opposite hypotenuse Hyp. Opp.
What is SOH CAH TOA? CAH cos = adjacent hypotenuse Hyp. Adj.
What is SOH CAH TOA? TOA tan = opposite adjacent Opp. Adj.
Assignment: pg. 156: 1-26