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Pre Calculus. Trigonometry for Any Angle Day 41. Plan. Quiz – Right Triangle Trig Review of Homework Section 4.2 Review the Unit Circle 4.4 Trig For Any Angle Homework 4.4 P 297-298 # 3, 7, 13, 17, 21, 23, 31, 35, 47, 53, 85, 88 Quiz Unit Circle Next time. Right Triangle Trigonometry.
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Pre Calculus Trigonometry for Any Angle Day 41
Plan • Quiz – Right Triangle Trig • Review of Homework • Section 4.2 • Review the Unit Circle • 4.4 Trig For Any Angle • Homework 4.4 P 297-298 # 3, 7, 13, 17, 21, 23, 31, 35, 47, 53, 85, 88 • Quiz Unit Circle Next time
Even and Odd Trig Functions An even function: f(x) = f(-x) cos(30o) = cos(-30o)? cos(135o) = cos(-135o)? The cosine and its reciprocal are evenfunctions.
Even and Odd Trig Functions An odd function: f(-x) = -f(x) sin(-30o) = -sin(30o)? sin(-135o) = -sin(135o)? The sine and its reciprocal are oddfunctions.
Even and Odd Trig Functions An odd function: f(-x) = -f(x) tan(-30o) = -tan(30o)? tan(-135o) = -tan(135o)? The tangent and its reciprocal are oddfunctions.
Even and Odd Trig Functions Cosine and secant functions are even cos (-t) = cos t sec (-t) = sec t Sine, cosecant, tangent and cotangent are odd sin (-t) = - sin t csc (-t) = - csc t tan (-t) = - tan t cot (-t) = - cot t Add these to your worksheet
Unit Circle Review How can we memorize it? • Symmetry • For Radiansthedenominatorshelp! • Knowing the quadrant givesthe correct+ / - sign
Practice… Get out your Unit Circle, Pencil and Paper! • ON YOUR OWN try these… • Write the question and the answer
Reference Angles Let θ be an angle in standard position. Its reference angle is the acute angle θ’ (called “theta prime”) formed by the terminal side of θ and the horizontal axis.
Reference Angles Let θ be an angle in standard position and its reference angle has the same absolute value for the functions, the sign ( +/ - ) must be determined by the quadrant of the angle. • Quadrant II θ’ = π – θ (radians) = 180o – θ (degrees) • Quadrant III θ’ = θ – π (radians) = θ – 180o (degrees) • Quadrant IV θ’ = 2π – θ (radians) = 360o – θ (degrees)
r θ (x,y) Trigonometry for any angle Given a point on the terminal side Let be an angle in standard position with (x, y) a point on the terminal side of and r be the length of the segment from the origin to the point Then….
Trig for any angle • The six trigonometric functions can be defined as Add these definitions to summary worksheet
(-3, 4) r θ Evaluating Trig Functions: Find sin, cos and tan given (-3, 4) is a point on the terminal side of an angle. • Find r • Find the ratio of the sides of the reference angle • Make sure you have the correct sign based upon quadrant Find r. (-3)2 + (4)2= r2 r =5 sin θ = 4/5 cos θ = -3/5 tan θ = -4/3
Name the quadrant… A little different twist… The cosine and sine of the angle are positive 1 The cosine and sine are negative 3 The cosine is positive and the sine is negative. 4 The sine is positive and the tangent is negative 2 The tangent is positive and the cosine is negative. 3 The secant is positive and the sine is negative. 4
θ r (4, -5) Look at this one… Given tan = -5/4 and the cos > 0, find the sin and sec . Which quadrant is it in? The tangent is negative, and the cosine is positive Quadrant IV at point (4, -5) Find r and use the triangle to find the sine and secant
(x, 1) 3 θ And this one… • Let be an angle in quadrant II such that sin = 1/3 find the cos and the tan . Set up a triangle based upon the information given . Calculate the other side Find the other trigonometric functions
Homework 22 Section 4.4 pp. 297-298; 3, 7, 13, 17, 21, 23, 31, 35, 47, 53, 85, 88