Wednesday, September 23, 2015

Unit Circle! And test Friday!

GREAT work today! You all did an awesome job working together to figure out something tough, the unit circle! Tomorrow we'll recap our work and continue to develop our understanding of the unit circle, and start to connect it to the rest of our trig stuff!

Tonight, your homework is to finish your unit circle (classwork) if you didn't already. The completed product must have each of the following:

  • Each angle measure labeled in degrees
  • Each angle measure labeled in radians
  • All coordinate pairs labeled for each angle 
If you get stuck, here are the "hint cards" for each question:
  • 2.) Consider the radius of the circle. Remember, each of these points on the axes (x or y axis) is a radius; we can use this information to figure out “how far right/left” or “how far up/down” we have moved, and then this will help us label the coordinates.
  • 4.) This is a 45° angle, so we must have to use special triangles somehow.
    Draw yourself the “reference triangle.”Now can you label the sides of the triangle (based on the properties of a 45/45/90 triangle)? Use these side lengths to determine the x (“how far right”) and y (“how far up”) coordinates.
  • 5.)Think the same way you did for #4. Draw that reference triangle, then use the properties of a 30/60/90 triangle to label the side lengths and determine the x and y coordinates (how far right, how far up?)
  • 6.) See 4 and 5. You got this.
  • 7.) Think about the activity where we shaded our angle measures on blank circles. For this, we split up our circles by π/4’s or π/3’s or π/6’s. You likely have these pictures in your notes (you better! :) ) Also, consider using “X” shapes…extend the lines you drew in the first quadrant into the 3rd quadrant. 
  • 8.) There are two ways to think about finding the coordinates where the angles intersect the unit circle for the remaining 3 quadrants…
    Method 1: Think about reflections…consider how the sign (+/-) of the x and y values differ for each quadrant. Then, consider the reference angle. Use the coordinates from quadrant 1 for the same reference angle, and then simply use reflections to change the signs (+/-) appropriately.
  • 8.) Method 2: For any angle measure, draw the reference triangle—remember, we always draw our triangles to the x-axis (remember the bowtie?). When we do this, we will create a special triangle (30/60/90 or 45/45/90). We can now use the properties of special triangles to label the side lengths, and thus find the x and y coordinates. Just remember to pay attention to the signs (+/-).
Also, don't forget....TEST FRIDAY! (There is no unit circle stuff on our test).

Here's a list of what's on your test: (textbook section # in parentheses)

  • Use a graphing calculator to evaluate trig functions (4.3)
    • Ex: sin(2.34) = ?, cos(154 degrees) = ?, sec(2pi/3) = ?, cot(139 degrees) = ?
  • SOHCAHTOA "Word Problems" (4.3)
    • Draw a triangle to model the scenario
    • Use trig ratios to find a missing side length
    • Use trig inverses to find missing angle measures
    • Know angles of elevation and angles of depression (how to draw them)
  • Solve triangles (4.3)
    • Use trig ratios and/or trig inverses to find all side lengths and angle measures
    • Also, use Pythagorean theorem! And know that angles of a triangle sum (add up to) 180 degrees!
  • Define the 6 trig ratios given a triangle (and "theta") (4.3)
    • Be sure you know the 6 ratios! Study, study, study!
  • Define the (remaining 5) trig ratios given one ratio (4.3)
    • Example: Given sin(x) = 3/5, draw a triangle, choose/identify an angle theta, find the third side of the triangle (Pythag.), and then define the remaining 5 ratios!
  • Convert angle measures to radians (4.1)
  • Convert angle measures to degrees (4.1)
  • Find complements and supplements in degrees (4.1)
  • Find coterminal angles (+/-) in degrees (4.1)
  • Find complements and supplements in radians (4.1)
    • Use common denominators/fractions to solve--no converting to degrees!
  • Find coterminal angles (+/-) in radians (4.1)
  • Sketch angles in standard position (radians and degrees) (4.1)
  • Find the measure of a reference angle
    • Remember, reference angles are formed by the terminal side of an angle and the X axis!

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