CCGPS AA 5.1.3 Example 1: Coordinates of Intersection of 330° Terminal Side with

CCGPS AA 5.1.3 Example 1: Coordinates of Intersection of 330° Terminal Side with
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2014-05-13 20:57
In collections CCGPS AA Unit 5 Lesson 1
This example demonstrates how to find the coordinates of the point where the terminal side of a 330° angle intersects the unit circle. The core mathematical concept is the unit circle definition of trigonometric functions: for any angle θ, the intersection point has x-coordinate equal to cosθ and y-coordinate equal to sinθ. The construction uses GeoGebra commands such as Circle to draw the unit circle, Angle to create the 330° angle, and If, Zip for handling angle normalization and quadrant determination. LaTeX text objects display the step-by-step computation. This resource is suitable for high school or introductory college students learning trigonometry, angle measure conversions, and unit circle symmetry, and can be used for classroom demonstration or self-study.

GeoGebra Commands & Parameters

  1. GCD(angleDeg, 180) → common
  2. LaTeX(steps) → counter
  3. Circle((0, 0), 1) → c
  4. If(factor < 1, angleDeg / common, (angleDeg - 180) / common) → newNum
  5. LaTeX("\text{Sketch the angle.}") → text3
  6. If(factor < 1, Sequence[(i * 180 / newDen), i, 1, newDen - 1], Sequence[180 + (i * 180 / newDen), i, 1, newDen - 1]) → list1
  7. Zip((cos((a * π / 180)), sin((a * π / 180))), a, list1) → list2
  8. Zip(Segment[(0, 0), a], a, list2) → list3
  9. Segment((0, 0), C) → a
  10. Segment((0, 0), (1, 0)) → b
  11. Angle(A, (0, 0), C) → θ
  12. If(0 < factor ≤ 0.5, LaTeX["\text{I}"], If[0.5 < factor ≤ 1, LaTeX["\text{II}"], If[1 < factor ≤ 1.5, LaTeX["\text{III}"], LaTeX["\text{IV}"]]]) → quadrant
  13. If(0 < factor ≤ 0.5, LaTeX["\text{The measure of the original angle is the measure of the reference angle.}"], If[0.5 < factor ≤ 1, LaTeX["\text{Subtract the measure of the original angle from 180° to find the }\cr\text{measure of the reference angle.}"], If[1 < factor ≤ 1.5, LaTeX["\text{Subtract 180° from the original angle measure to find the}\cr\text{measure of the reference angle.}"], LaTeX["\text{Subtract the measure of the original angle from 360° to find the }\cr\text{measure of the reference angle.}"]]]) → subtraction
  14. If(0 < factor ≤ 0.5, angleDeg, If[0.5 < factor ≤ 1, 180 - angleDeg, If[1 < factor ≤ 1.5, angleDeg - 180, 360 - angleDeg]]) → refDeg
  15. If(0 < factor ≤ 0.5, Angle[A, (0, 0), C], If[0.5 < factor ≤ 1, Angle[C, (0, 0), B], If[1 < factor ≤ 1.5, Angle[B, (0, 0), C], Angle[C, (0, 0), A]]]) → θ_{ref}
  16. LaTeX("\text{Determine the coordinates of point }\textcolor{#006633}{C}.") → text14
  17. If(0 < factor ≤ 0.5, LaTeX["\text{(+,+)}"], If[0.5 < factor ≤ 1, LaTeX["\text{(-,+)}"], If[1 < factor ≤ 1.5, LaTeX["\text{(-,-)}"], LaTeX["\text{(+,-)}"]]]) → signs
  18. If(0 < factor ≤ 0.5, LaTeX["\textcolor{#006633}{(\cos(\theta),\sin(\theta))}=\textcolor{#CC0000}{(\cos(\theta_{ref}),\sin(\theta_{ref}))}"], If[0.5 < factor ≤ 1, LaTeX["\textcolor{#006633}{(\cos(\theta),\sin(\theta))}=\textcolor{#CC0000}{(-\cos(\theta_{ref}),\sin(\theta_{ref}))}"], If[1 < factor ≤ 1.5, LaTeX["\textcolor{#006633}{(\cos(\theta),\sin(\theta))}=\textcolor{#CC0000}{(-\cos(\theta_{ref}),-\sin(\theta_{ref}))}"], LaTeX["\textcolor{#006633}{(\cos(\theta),\sin(\theta))}=\textcolor{#CC0000}{(\cos(\theta_{ref}),-\sin(\theta_{ref}))}"]]]) → text16
  19. LaTeX((("\theta=" * angleDeg) * "^{\circ}")) → Problem
  20. LaTeX((((("\textcolor{#CC0000}{\cos(\theta_{ref})=\cos\left(" * refDeg) * "^{\circ}\right)\approx") * cosRef) * "}")) → text12
  21. LaTeX((((("\textcolor{#CC0000}{\sin(\theta_{ref})=\sin\left(" * refDeg) * "^{\circ}\right)\approx") * sinRef) * "}")) → text11
  22. LaTeX("\text{Move the slider to solve the problem.}") → text0
  23. LaTeX("\text{A half rotation (π radians) is 180° and a full rotation (2π radians) is 360°. }\cr\text{Notice that 0° and 360° are in the same location on the unit circle, }\cr\text{but represent different angle measures.}") → text2
  24. If(angleDeg / 180 < 1, LaTeX[(((((((((((((("\text{The terminal side of }" * angleDeg) * "°\text{ is }\frac{") * angleDeg) * "}{180}=\frac{") * newNum) * "}{") * newDen) * "}\text{ of the way from 0° to 180°.}\cr\text{Thus, imagine the semicircle between 0° and 180° split into ") * newDen) * " parts and then}\cr\text{sketch the angle }\frac{") * newNum) * "}{") * newDen) * "}\text{ of the way around the semicircle.}")], LaTeX[(((((((((((((("\text{The terminal side of }" * angleDeg) * "°\text{ is }\frac{") * angleDeg) * "-180}{180}=\frac{") * newNum) * "}{") * newDen) * "}\text{ of the way from 180° to 360°. }\cr\text{Thus, imagine the semicircle between 180° and 360° split into ") * newDen) * " parts and then }\cr\text{sketch the angle }\frac{") * newNum) * "}{") * newDen) * "}\text{ of the way around the semicircle.}")]) → text4
  25. LaTeX((((("\text{The reference angle for }" * angleDeg) * "°\text{ is }") * refDeg) * "°.")) → text9
  26. LaTeX("\text{Determine }\textcolor{#CC0000}{\sin(\theta_{ref})}\text{ and }\textcolor{#CC0000}{\cos(\theta_{ref})}\text{ in order to determine }\textcolor{#006633}{\sin(\theta)}\text{ and }\textcolor{#006633}{\cos(\theta)}.") → text10
  27. LaTeX("\text{Because the reference angle is always between 0° and 90°, the sine and cosine of the}\cr\text{reference angle are always non-negative.}") → text13
  28. LaTeX((("\text{The coordinates of point }\textcolor{#006633}{C}\text{ are approximately } \textcolor{#006633}{" * C) * "}.")) → text17
  29. LaTeX("\text{Use the buttons below to return to the original problem or}\cr\text{randomly generate a similar practice problem.}") → text18
  30. LaTeX("\text{0°") → zero
  31. LaTeX("\text{Sketch a unit circle, and then label 0°, 180°, and 360°.}") → text1
  32. LaTeX("\text{Determine the measure of the reference angle, which is the measure of the}\cr\text{angle between the terminal side and the x-axis. }") → text6
  33. LaTeX((((("\text{The terminal side falls in Quadrant } " * quadrant) * ".\cr") * subtraction) * "")) → text7
  34. LaTeX("\text{The coordinates of point }\textcolor{#006633}{C}\text{ are given by } \textcolor{#006633}{(\cos(\theta),\sin(\theta))}\text{, which can be evaluated }\cr\text{from the reference angle }\textcolor{#CC0000}{\theta_{ref}}.") → text5
  35. LaTeX((((("\text{Since point }\textcolor{#006633}{C}\text{ and the terminal side lie in Quadrant }" * quadrant) * ", \cr\text{the signs of the coordinates of point }\textcolor{#006633}{C}\text{ follow the pattern } ") * signs) * ".")) → text15
  36. If(0 < factor ≤ 0.5, LaTeX[(("\textcolor{#CC0000}{" * angleDeg) * "°}")], If[0.5 < factor ≤ 1, LaTeX[(((("\textcolor{#CC0000}{180°-" * angleDeg) * "°=") * refDeg) * "°}")], If[1 < factor ≤ 1.5, LaTeX[(((("\textcolor{#CC0000}{ " * angleDeg) * "°-180°=") * refDeg) * "°}")], LaTeX[(((("\textcolor{#CC0000}{ 360°-" * angleDeg) * "°=") * refDeg) * "°}")]]]) → text8

AI Drawing Prompt Reference

Draw a unit circle and mark the terminal side of a 330° angle. Determine the coordinates of the point C where the terminal side intersects the unit circle. First, draw a circle with radius 1, then draw the 330° angle, identify the quadrant of the terminal side, calculate the reference angle, and determine the sign of the coordinates of point C based on the quadrant.
The prompt above was compiled from the original drawing commands and is for reference only.