Graph of Cosine Function

Graph of Cosine Function
Loading the math board and drawing, please wait…
2014-04-04 21:36
This example demonstrates how to sketch the graph of the function a(x) = –2 + 4 cos 2x over the interval [–π, π]. Key mathematical concepts include trigonometric functions and function graphs. Using GeoGebra commands such as Zip, TableText, and If, the graph can be dynamically displayed. Suitable for high school mathematics education and learning.

GeoGebra Commands & Parameters

  1. Zip(FractionText[a], a, mins) → minlist
  2. Zip(LaTeX[(a * "\pi")], a, minlist) → minlistfull
  3. Zip(((u * π), c - abs(a)), u, mins) → minpts
  4. Zip(LaTeX[((((((((a * "\cos\left((") * b) * ")\left(") * u) * "\right)\right)+(") * c) * ")=") * y(v))], u, minlistfull, v, minpts) → yminlist
  5. Zip(((u * π), c + abs(a)), u, maxes) → maxpts
  6. Zip(FractionText[a], a, maxes) → maxlist
  7. Zip(LaTeX[(a * "\pi")], a, maxlist) → maxlistfull
  8. Zip(LaTeX[((((((((a * "\cos\left((") * b) * ")\left(") * u) * "\right)\right)+(") * c) * ")=") * y(v))], u, maxlistfull, v, maxpts) → ymaxlist
  9. LaTeX(steps) → counter
  10. Simplify((b * x)) → argum
  11. FractionText(dl) → domleft
  12. FractionText(dr) → domright
  13. If(domleft ≟ "-1", LaTeX["-\pi"], LaTeX[(domleft * "\pi")]) → domLeft
  14. If(domright ≟ "1", LaTeX["\pi"], LaTeX[(domright * "\pi")]) → domRight
  15. LaTeX((((((("\textcolor{#000099}{f(x)=" * f) * "}\text{ over }\textcolor{#000099}{\left[") * domLeft) * ",") * domRight) * "\right]}")) → Problem
  16. LaTeX("\text{Identify the amplitude of the function.}") → text1
  17. LaTeX("\text{This will help determine the y-axis scale.}") → text2
  18. LaTeX("\text{Determine the period of the function.}") → text4
  19. LaTeX("\text{Identify any other coefficients or terms that would affect the shape of the graph.}") → text8
  20. LaTeX("\text{This is necessary to determine if the graph is translated horizontally or vertically, or if}\cr\text{other mathematical terms affect the graph’s shape.}") → text9
  21. LaTeX("\text{This will determine how many cycles of the function show in the given domain.}") → text5
  22. LaTeX("\text{Draw and label the axes for your graph.}") → text12
  23. LaTeX("\text{The x-axis scale is determined by the given restricted domain.}") → text13
  24. LaTeX((((("\text{The x-axis scale will cover at least from }\textcolor{#000099}{" * dl) * "\pi}\text{ to }\textcolor{#000099}{") * dr) * "\pi}.")) → text14
  25. LaTeX("\text{The y-axis scale is determined by the amplitude and the vertical shift, if any.}") → text15
  26. LaTeX((((("\text{The y-axis scale should cover at least from }\textcolor{#000099}{y = " * Simplify[c - a]) * "}\text{ to }\textcolor{#000099}{y = ") * Simplify[c + a]) * "}.")) → text16
  27. Zip(FractionText[a], a, zeros) → zerolist
  28. Zip(LaTeX[(a * "\pi")], a, zerolist) → zerolistfull
  29. Zip(((a * π), c), a, zeros) → zeropts
  30. TableText({zerolistfull}) → zerosnq
  31. LaTeX("\text{Determine what values of the restricted domain are the maximum and minimum of the}\cr\text{function value(s). List the points corresponding to these extremes, and plot them on the}\cr\text{graph.}") → text21
  32. TableText({maxlistfull}) → maxnq
  33. TableText({minlistfull}) → minnq
  34. LaTeX("\text{Sketch a smooth curve over the given restricted domain.}") → text46
  35. LaTeX((((("\text{The cosine argument is }\textcolor{#000099}{" * argum) * "}\text{. Solve }\textcolor{#000099}{") * argum) * "=2\pi}\text{ for }\textcolor{#000099}{x}\text{ to find the period.}")) → text6
  36. LaTeX("\text{Determine the values of the restricted domain for which the cosine value(s) equal 0.}\cr\text{List the points corresponding to these zeros, and plot them on the graph.}") → text17
  37. LaTeX("\text{The cosine function is zero when its argument is }\textcolor{#000099}{\frac{\pi}{2}\pm n\pi}\text{ where }\textcolor{#000099}{n}\text{ is an integer, }\textcolor{#000099}{0,1,2,\ldots}.") → text18
  38. LaTeX((((("\textcolor{#000099}{" * b) * "x=\frac{\pi}{2}\pm n\pi}\cr\textcolor{#000099}{x=") * zerosnq) * "}")) → text19
  39. LaTeX("\text{The cosine function has maximums when its argument is }\textcolor{#000099}{\pm2n\pi}\text{ where }\textcolor{#000099}{n}\text{ is an integer.}") → text22
  40. LaTeX("\text{The cosine function has minimums when its argument is }\textcolor{#000099}{\pi\pm2n\pi}\text{ where }\textcolor{#000099}{n}\text{ is an integer.}") → text25
  41. TableText({ymaxlist}, "v") → ymaxtext
  42. TableText({yminlist}, "v") → ymintext
  43. Zip(LaTeX[((((((((a * "\cos\left((") * b) * ")\left(") * u) * "\right)\right)+(") * c) * ")=") * y(v))], u, zerolistfull, v, zeropts) → yzero
  44. TableText({yzero}, "v") → yzerotext
  45. FractionText(permult) → permulttext
  46. LaTeX((((((((((((("\textcolor{#000099}{x=\frac{2}{" * b) * "}\pi}\text{ The period is }\textcolor{#000099}{") * permult) * "\pi}.\cr\text{The number of cycles in the domain is }\textcolor{#000099}{\frac{domain}{period}=\frac{") * domRight) * "-") * domLeft) * "}{") * permulttext) * "\pi}=") * cycles) * "}.")) → text7
  47. LaTeX("\text{Move the slider to solve the problem.}") → text0
  48. LaTeX("\text{Use the buttons below to return to the original problem or}\cr\text{randomly generate a similar practice problem.}") → text47
  49. LaTeX((("\text{The corresponding y-values are: }\textcolor{#000099}{" * yzerotext) * "}")) → text20
  50. LaTeX((("\text{The corresponding y-values are: }\textcolor{#000099}{" * ymintext) * "}")) → text27
  51. LaTeX((((("\text{The coefficient of the cosine function is }\textcolor{#000099}{" * a) * "}\text{; therefore, the amplitude is }\textcolor{#000099}{") * a) * "}.")) → text3
  52. LaTeX("\text{The cosine argument has no constant term, so there is no horizontal shift.}") → text10
  53. If(c ≟ 0, LaTeX["\text{The function has no constant term, so there is no vertical shift.}"], If[c > 0, LaTeX[(((("\text{The constant term }\textcolor{#000099}{+" * c) * "}\text{ in the function means the cosine function will be shifted up by }\textcolor{#000099}{") * abs(c)) * "}.")], LaTeX[(((("\text{The constant term }\textcolor{#000099}{" * c) * "} \text{ in the function means the sine function will be shifted down by }\textcolor{#000099}{") * abs(c)) * "}.")]]) → text11
  54. LaTeX((("\text{The corresponding y-values are: }\textcolor{#000099}{" * ymaxtext) * "}")) → text24
  55. LaTeX((((("\textcolor{#000099}{" * b) * "x=\pi\pm 2n\pi} \to \textcolor{#000099}{x=") * minnq) * "}")) → text26
  56. LaTeX((((("\textcolor{#000099}{" * b) * "x=\pm 2n\pi} \to \textcolor{#000099}{x=") * maxnq) * "}")) → text23

AI Drawing Prompt Reference

Draw the graph of the function a(x) = –2 + 4 cos 2x over the interval [–π, π], highlighting amplitude, period, and vertical shift. Start by labeling the x and y axes, then determine the y-axis scale based on the amplitude and vertical shift. Identify and plot the zeros, maxima, and minima of the function. Finally, sketch a smooth curve through these points to complete the graph.
The prompt above was compiled from the original drawing commands and is for reference only.