Graphing and Analyzing the Sine Function f(x) = 4 sin x

Graphing and Analyzing the Sine Function f(x) = 4 sin x
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2014-09-13 03:50
This GeoGebra example demonstrates the graphical representation and property analysis of the trigonometric function f(x) = 4 sin x. The core mathematical concepts involved include sine waves, amplitude scaling, periodicity, and trigonometric function transformations. To construct this interactive visualization, LaTeX is used for formula rendering, while commands like Corner, If, and Mirror handle the logical layout. Key objects such as stepper, counter, and steps manage the step-by-step problem-solving flow, and ZoomFit dynamically adjusts the grid view. Interactive elements like buttons, dynamic texts, and sliders allow students to explore the function's behavior in real-time. It is highly suitable for high school level mathematics (specifically Math III or precalculus) to teach and learn trigonometric graphing.

GeoGebra Commands & Parameters

  1. LaTeX(steps) → counter
  2. LaTeX("\text{Move the slider to solve the problem.}") → text0
  3. Corner(1) → A
  4. Corner(3) → B
  5. If(choose ≟ 1, Simplify[(a * sin((b * x)))], Simplify[(a * cos((b * x)))]) → f
  6. LaTeX((("\textcolor{#000099}{f(x)=" * f) * "}")) → Problem
  7. LaTeX("\text{Graph several periods of }\textcolor{#000099}{f(x)}.") → text1
  8. If(choose ≟ 1, ((-π)) / ((2 * b)), 0) → left
  9. If(choose ≟ 1, π / ((2 * b)), π / b) → right
  10. If(choose ≟ 1, "-", "") → posneg
  11. If(choose ≟ 1, LaTeX[(("-\frac{\pi}{" * Simplify[(2 * b)]) * "}")], "0") → leftText
  12. If(choose ≟ 1, LaTeX[(("\frac{\pi}{" * Simplify[(2 * b)]) * "}")], LaTeX[(("\frac{\pi}{" * Simplify[b]) * "}")]) → rightText
  13. LaTeX("\text{Solve for the inverse function }\textcolor{#006633}{g(x)}\text{ algebraically.}") → text11
  14. LaTeX((("\textcolor{#000099}{f(x)=" * f) * "}")) → text14
  15. LaTeX("\text{Switch }\textcolor{#000099}{x}\text{ and }\textcolor{#000099}{f(x)}.") → text15
  16. If(choose ≟ 1, "sin", "cos") → functext
  17. LaTeX((("\text{Take the inverse " * functext) * " of both sides.}")) → text21
  18. LaTeX("\text{Simplify and use symmetry of equality.}") → text23
  19. If(b ≠ 1, LaTeX[Simplify[1 / b]], "") → invCoeff
  20. Mirror(h, y = x) → Inverse
  21. LaTeX((((((("\textcolor{#006633}{g(x)=\frac{" * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)}{") * b) * "}}")) → text26
  22. LaTeX((((((("\textcolor{#006633}{" * b) * "g(x)=") * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)}")) → text24
  23. LaTeX((((((((((("\textcolor{#006633}{" * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)=") * functext) * "^{-1}\left(") * functext) * "(") * b) * "g(x))\right)}")) → text22
  24. LaTeX((((("\textcolor{#006633}{\frac{x}{" * a) * "}=") * functext) * "(g(x))}")) → text20
  25. LaTeX("\text{Rename }\textcolor{#000099}{f(x)}\text{ as }\textcolor{#006633}{g(x)}.") → text17
  26. LaTeX((((((("\textcolor{#006633}{x=" * a) * "") * functext) * "(") * b) * "g(x))}")) → text18
  27. LaTeX((((((("\textcolor{#006633}{g(x)=" * invCoeff) * "") * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)}")) → invlabel
  28. LaTeX((("\text{Divide both sides by }\textcolor{#006633}{" * b) * "}.")) → text25
  29. LaTeX((("\textcolor{#000099}{f(x)=" * f) * "}")) → restrictlabel
  30. LaTeX((((((("\textcolor{#000099}{x=" * a) * " ") * functext) * "(") * b) * "f(x))}")) → text16
  31. If(choose ≟ 1, "sine", "cosine") → name
  32. If(choose ≟ 1, (((-3) * a / 4), asin((((-3) * a / 4)) / a) / b), (((-3) * a / 4), acos((((-3) * a / 4)) / a) / b)) → C
  33. LaTeX("\text{Use the buttons below to return to the original problem or}\cr\text{randomly generate a similar practice problem.}") → RandomizationText
  34. LaTeX("\text{Determine the range of }\textcolor{#000099}{f(x)}\text{ within the restricted domain.}") → text8
  35. LaTeX((((((((("\text{The inverse function of }\textcolor{#000099}{f(x)=" * f) * "}\text{ is }\textcolor{#006633}{g(x)=") * invCoeff) * "") * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)}.")) → text27
  36. LaTeX("\text{The domain and range of an inverse function are the range and (restricted) }\cr\text{domain of the original function.}") → text29
  37. LaTeX((("\text{The trigonometric function }\textcolor{#000099}{f(x) = " * f) * "}\text{ is not fully invertible because}\cr\text{of its periodic nature. Viewing several periods of the function is the first step }\cr\text{toward identifying a restricted domain on which the function is invertible.}")) → text2
  38. LaTeX((((("\text{Notice that multiplying the " * name) * " function by }\textcolor{#000099}{") * a) * "}\text{ does not affect the}\cr\text{restricted domain.}")) → text6
  39. LaTeX((((((("\text{For the function }\textcolor{#000099}{f(x) = " * f) * "}\text{, this restricted domain is }\textcolor{#CC0000}{\left[") * leftText) * ",") * rightText) * "\right]}.")) → text5
  40. LaTeX("\text{Adjust the window properties to display the graph only for }\textcolor{#000099}{x}\text{-values}\cr\text{in the restricted domain. Make sure you do not change the }\textcolor{#000099}{y}\text{-axis}\cr\text{window settings.}") → text7
  41. LaTeX("\text{Look at the graph of }\textcolor{#000099}{f(x)}\text{ on its restricted domain, and identify the range}\cr\text{of }\textcolor{#000099}{y}\text{-values that are visible for the function.}") → text9
  42. LaTeX("\text{Original function }\textcolor{#000099}{f(x)}") → text13
  43. LaTeX((("\text{Divide both sides by }\textcolor{#006633}{" * a) * "}.")) → text19
  44. LaTeX("\text{Determine the domain and range of the inverse }\text{function }\textcolor{#006633}{g(x)}.") → text28
  45. LaTeX("\text{Restrict the domain until there is a one-to-one correspondence. }") → text3
  46. LaTeX("\text{Look at the graph of }\textcolor{#000099}{f(x)}\text{ to find the widest possible }\textcolor{#000099}{x}\text{-interval containing }\cr\textcolor{#000099}{x = 0}\text{ for which no }\textcolor{#000099}{y}\text{-value is repeated.}") → text4
  47. LaTeX((((((((((((((("\text{For the function }\textcolor{#000099}{f(x) = " * f) * "}\text{ on the restricted domain }\textcolor{#000099}{\left[") * leftText) * ",") * rightText) * "\right]}\text{, }\cr\textcolor{#000099}{y}\text{-values on the visible part of the function range from }\textcolor{#000099}{–") * a) * "}\text{ to }\textcolor{#000099}{") * a) * "}\text{.}\cr\text{Therefore, the range of }\textcolor{#000099}{f(x)}\text{ within the restricted domain is }\textcolor{#000099}{\left[–") * a) * ", ") * a) * "\right]}.")) → text10
  48. LaTeX((((((((((((((((((((((((("\text{For the original function }\textcolor{#000099}{f(x) = " * f) * "}\text{, the restricted domain is }\cr\textcolor{#000099}{\left[") * leftText) * ",") * rightText) * "\right]}\text{ and the range is }\textcolor{#000099}{[-") * a) * ",") * a) * "]}\text{.}\cr\text{Therefore, for the inverse function }\textcolor{#006633}{g(x)=") * invCoeff) * "") * functext) * "^{-1}\left(\frac{x}{") * a) * "}\right)}\text{, }\cr\text{the domain is }\textcolor{#006633}{[–") * a) * ", ") * a) * "]}\text{ and the range is }\textcolor{#006633}{\left[") * leftText) * ",") * rightText) * "\right]}.")) → text30
  49. LaTeX("\text{Recall that you can find the inverse of a function }\textcolor{#000099}{f(x)}\text{ by switching the domain}\cr\text{and function variables, renaming the function as }\textcolor{#006633}{g(x)}\text{, and then solving for }\textcolor{#006633}{g(x)}.") → text12