20 Days Three days One radian is the measure of the central angle of a circle subtended by an arc of equal length to the radius of the circle. 1. 180 radians 2. 1 180 radians 0.0175 radians 3. 1 radian 180 57.2958 To Change From : Multiply by : Example : Degrees to Radians 180 2 120 120 180 3 Radians to Degrees 180 4 4 180 240 3 3 A circle with radius of 1 Equation x2 + y2 = 1 0,1 1,0 0,1 cos , sin 1,0 Read 5.1 and Complete "What do you know about Trig" WS Angle – Set of points determined by two rays. Example <AOB In trig, we often think of angles as the rotation of rays. This gives us some new vocab. Initial side – the fixed ray from which we measure an angle. Terminal side – the rotated ray that determines the measure of an angle. Vertex – the point about which the terminal side is rotated and is common to both sides. Coterminal angles - two angles with the same initial and terminal sides. Straight angle – an angle whose sides line on a straight line and extend in opposite directions from the vertex. Degrees – One unit of measuring an angle. One complete revolution in the counter clockwise direction is 360*. Using the x-y plane, the standard position of an angle has its vertex at the origin and its initial side as the positive x-axis. If the terminal angle is rotated counter clockwise, the angle is positive. If the terminal angle is rotated clockwise, the angle is negative. If 45 is in standard position, find two positive and two negative angles that are coterminal with . You should be familiar with the following terms: Right angle Acute angle Obtuse angle Compliment ary angles , Supplement ary angles , 90 0 90 90 180 90 180 If an arc of length s on a circle of radius r subtends a central angle of radian measure , then s r Given a circle with radius r 4cm and find the arc length s. 6 , Given s 12 and 7, find the radius r. Given s 3cm and r 5, find in radians. If is the radian measure of a central angle of a circle with radius r and if A is the area of the circular sector determined by , then 1 2 A r 2 p359 (#1,3,9 - 11,13,15,16,29, 31a, 33a) Read p349 - 351, 353(note blue box and below), 354 and example 5 When more precise measurements are required, we can extend our measurement to more decimal places, or we can divide the degree into equal parts called minutes (denoted ‘) and seconds (denoted “). Thus, 1 60' and 1' 60". 2914'45" refers to the angle that has measure 29 degrees, 14 minutes, and 45 seconds. Find the angle that is complement ary to . a.) 2914'45" b.) 81.34 If 4, approximat e in terms of degrees, minutes, and seconds. p359 (#4,6,12,14,21,24,25,28,30,32,35-37,39) Four Days We can refer to the three sides of any right triangle in relation to a specific acute angle as the adjacent, opposite, and hypotenuse sides. The six trig functions are the sine, cosine, tangent, cosecant, secant, and cotangent. opp sin hyp 1 hyp csc sin opp adj cos hyp 1 hyp sec cos adj opp tan adj 1 adj cot tan opp cos tan Find the six trig values for θ in the triangle 4 below. sin 5 3 cos 5 5 tan 4 4 3 csc 5 3 4 sec 5 3 cot 3 4 Find the six trig values for θ in the triangle below. sin 24 12 cos 4 2 3 2 2 1 3 tan 2 3 csc 2 3 2 3 4 4 2 2 4 sec 2 3 cot 2 3 2 2 3 3 Find the six trig values for θ if θ is in standard position and P(2,-5) is on the terminal side. sin 2 29 cos 5 29 tan 2 5 29 5 2 P (2,5) csc 29 2 sec 29 5 cot 5 2 Find the values of x and y in the triangle below using trig functions. 6 x 3 30 y 3 3 y x cos(30) sin( 30) 6 6 x 6 sin( 30) y 6 cos(30) y 6 23 x 6 12 x3 y3 3 You are visiting Sequoia National Park in California to see the Giant Redwood Trees. You are standing 500ft away from the biggest tree that you can find and the angle between the ground and the top of the tree is 33*. How tall is the tree? p375 (#2,3,9, 11, 21,22,24,27—exact answers until #21) Read p362 - 365 Find the six trig values for θ if θ is in standard position and is on the line y=-4x. 4 1 17 y 4 x sin 2 29 cos 5 29 tan 2 5 csc 29 2 sec 29 5 cot 5 2 Given that tan values. 11 5 find the remaining trig sin cos tan csc sec cot cos tan Recall that the unit circle has its center at (0,0) and a radius of 1. If we divide the special right triangles so the hypotenuse equals 1 we get that the points on the unit circle have coordinates (cos , sin ) . (cos , sin ) The the coordinates on the unit circle are of the form (cos , sin ). We get the following values for 0, 30, 45, 60, and 90 degrees. You must memorize the following ASAP!! Rad Cos Sin 0 0 1 0 30 3 2 1 2 45 2 2 2 2 60 1 2 3 2 90 0 1 Deg 6 4 3 2 p375 (#4,12 ̶ 18 even, 28, 67,70,74,78) We can see that the 6 trig functions are reciprocals of one another. Sin and Csc are reciprocals, Cos and Sec are reciprocals, and Tan and Cot are also reciprocals. 1 sin csc 1 cos sec 1 tan cot 1 csc sin 1 sec cos 1 cot tan RECIPROCAL IDENTITIES 1 csc sin 1 sec cos 1 cot tan QUOTIENT IDENTITIES cos sin cot tan sin cos PYTHAGOREAN IDENTITIES sin cos 1 2 2 tan 1 sec 2 2 1 cot 2 csc 2 All of the identities we learned are found in the back page of your book under the heading Trigonometric Identities and then Fundamental Identities. You'll need to have these memorized or be able to derive them for this course. We can verify that the following identity is true by making the left side match the right side. sin tan cos Deriving the Pythagorean Identity using the Pythagorean Theorem and the unit circle. x2 y 2 1 When verifying identities, it is important to remember that all 6 trig functions can be written using sin and/or cos. sin sin cos cos 1 csc sin 1 sec cos sin tan cos cos cot sin Verify the following identity by re-writing the left hand side to match the right hand side. tan cot 1 sin cot cos Verify the following identity by re-writing the left hand side to match the right hand side. sin cos 1 tan cos Verify the following identity by re-writing the left hand side to match the right hand side. cos 2 2 sin 2 2 2 cos 2 2 1 worksheet 5.1 & 5.2 problems Pg 377 (# 50,54,57,58,59) As a class, we are going to do the following problems on the board. Volunteers? p375 #10,13,15,17 p377 (#45 ̶ 53 odd, 57) A ladder leaning against the wall makes an angle of 80* with the ground. If the foot of the ladder is 6ft from the wall, how high is the ladder? Your line of sight to the top of a mountain makes a 34* angle with the horizontal. If the line of sight is measured at 5500ft, how tall is the mountain? A boy flying a kite lets out 400ft of string which makes an angle of 42* with the ground. Assuming the string is straight and the ground is level, how high above the ground is the kite? A wire is attached to the top of a flagpole and is staked to the ground 30ft from its base. If the wire makes a 64* angle with the ground, how tall is the flagpole? An airplane climbs at a 9* angle after takeoff. How far has the plane traveled horizontally when it has attained an altitude of 3000ft? p377 (#29, 68,69,71,73,77,80, 81,83 #81 & 83) Four Days sin( t ) sin t cos( t ) cos t csc( t ) csc t sec( t ) sec t sin 4 cos 56 tan( t ) tan t cot (t ) cot t Applications #1 worksheet p394 (#3,9,12,15,19 - 21, 24,25) A reference angle is an acute, positive angle formed between the terminal side and the xaxis. Sine and Cosine are periodic functions, that is there exists a positive real number k such that f(t+k)=f(t) for every t in the domain of f. sin 2n sin cos 2n cos This video graphs all three functions simultaneously while rotating the angle in standard position on the unit circle. http://www.dnatube.com/video/12168/Triggraphs http://www.touchmathematics.org/topics/tri gonometry Even Functions Odd Functions f ( x) f ( x) f ( x) f ( x) cos cos sin sin sec sec csc csc tan tan cot cot Given a trig value, find θ. sin cos 6 , 56 , 136 , 76 1 2 3 2 6 , 116 , 136 , 6 tan 1 4 , 4 , 54 , 4 sin 2 2 4 , 54 , 74 , 4 Review 5.1 - 5.3 worksheet Find the angle(s) that satisfies each equation: sin 2 2 cos 1 tan 3 csc 2 sin .834 cos .6 tan 1.76 tan 21 cos 2 Applications worksheet 2 (#1 - 3, 5 – 7) A drawbridge is 150ft long across a river. The two sections are of equal length and can be rotated upward to an angle of 35*. If the water level is 15 feet below the bridge when it is closed. Find the distance between the end of each section of the bridge when raised and the surface of the water. A plane is on approach to the Harrisburg Airport at a current elevation of 10000ft. If the plane is 12 miles away what angle of decent should the pilot take to land at the airport? Find the height of the Matterhorn. Find the distance to the island. Three Days A reference angle is an acute, positive angle formed between the terminal side and the xaxis. p404 (#2,3,8 - 18 even(w/out a calculator), 19,21,25,29,33,43) Reference angle worksheet Finish Applications paper #8 plus p405 #36 Applications #3 worksheet Two Days p436 (#3,6,11,14,25,27,29,34 exact answers for #3 & 6, look at diagram for 25,29,34) p442 (#1 - 4, 7,8,21 - 24, 27,30, 67, 68) Prentice Hall p21 (#3,15,16,19,20,25) No calculator