Function Plotting--Sine Wave

Function plotting is another handy Solver feature. The sine wave is nice little repeating equation. It is based on an angle rotating through a circle of 360 degrees. In other words the range of a single cycle is 0 to 360. I will use this equation to demonstrate using the calculator while in solver. First let's get into RPN mode. If you are not already in RPN, press <MENU> Options Alg/RPN. RPN will appear on the lower left of your screen. To get out of RPN mode press <MENU> Options Alg/RPN again. For this example, use <MENU> Options Degrees. The sine wave equation is:

y=sin(x)

Enter this equation in the Solver editor and then press F10 to select Graph. Press F9 (XVAR) until Y shows as the plot-variable. Set XMIN to 0. Now let's set XMAX to plot four complete cycles. If one cycle is 360 degrees four cycles will be four times 360. Since the calculator is active it can be used to calculate the value of XMAX. Simply enter 360, press <ENTER>, enter 4, Press *, press F6 to set XMAX, and finally press F3 (AUTO) to plot the graph.

If you have done everything right you should have a nice smooth plot. If the plot is jagged it means the resolution is insufficient or if the graph took forever to plot, the resolution is too high. The higher the value the smoother the curve, but since resolution indicates the number of times the equation must be solved to plot the curve, a high value will slow the plotting. The screen resolution limits the resolution of function plotting so that selecting higher and higher values will not improve the plot after a point. I find 100 to be a good compromise value for resolution.

Try plotting the sine wave with a resolution of 25, 100, and 1000.

You will get the idea.