CCGPS AA 5.1.3 Example 1: Coordinates of Intersection of 330° Terminal Side with
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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
GCD(angleDeg, 180) → commonLaTeX(steps) → counterCircle((0, 0), 1) → cIf(factor < 1, angleDeg / common, (angleDeg - 180) / common) → newNumLaTeX("\text{Sketch the angle.}") → text3If(factor < 1, Sequence[(i * 180 / newDen), i, 1, newDen - 1], Sequence[180 + (i * 180 / newDen), i, 1, newDen - 1]) → list1Zip((cos((a * π / 180)), sin((a * π / 180))), a, list1) → list2Zip(Segment[(0, 0), a], a, list2) → list3Segment((0, 0), C) → aSegment((0, 0), (1, 0)) → bAngle(A, (0, 0), C) → θIf(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}"]]]) → quadrantIf(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.}"]]]) → subtractionIf(0 < factor ≤ 0.5, angleDeg, If[0.5 < factor ≤ 1, 180 - angleDeg, If[1 < factor ≤ 1.5, angleDeg - 180, 360 - angleDeg]]) → refDegIf(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}LaTeX("\text{Determine the coordinates of point }\textcolor{#006633}{C}.") → text14If(0 < factor ≤ 0.5, LaTeX["\text{(+,+)}"], If[0.5 < factor ≤ 1, LaTeX["\text{(-,+)}"], If[1 < factor ≤ 1.5, LaTeX["\text{(-,-)}"], LaTeX["\text{(+,-)}"]]]) → signsIf(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}))}"]]]) → text16LaTeX((("\theta=" * angleDeg) * "^{\circ}")) → ProblemLaTeX((((("\textcolor{#CC0000}{\cos(\theta_{ref})=\cos\left(" * refDeg) * "^{\circ}\right)\approx") * cosRef) * "}")) → text12LaTeX((((("\textcolor{#CC0000}{\sin(\theta_{ref})=\sin\left(" * refDeg) * "^{\circ}\right)\approx") * sinRef) * "}")) → text11LaTeX("\text{Move the slider to solve the problem.}") → text0LaTeX("\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.}") → text2If(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.}")]) → text4LaTeX((((("\text{The reference angle for }" * angleDeg) * "°\text{ is }") * refDeg) * "°.")) → text9LaTeX("\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)}.") → text10LaTeX("\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.}") → text13LaTeX((("\text{The coordinates of point }\textcolor{#006633}{C}\text{ are approximately } \textcolor{#006633}{" * C) * "}.")) → text17LaTeX("\text{Use the buttons below to return to the original problem or}\cr\text{randomly generate a similar practice problem.}") → text18LaTeX("\text{0°") → zeroLaTeX("\text{Sketch a unit circle, and then label 0°, 180°, and 360°.}") → text1LaTeX("\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. }") → text6LaTeX((((("\text{The terminal side falls in Quadrant } " * quadrant) * ".\cr") * subtraction) * "")) → text7LaTeX("\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}}.") → text5LaTeX((((("\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) * ".")) → text15If(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.