Why no graph?

Questions
,
1

I am studying a basic Mathematica book and I am following examples and cannot get this to plot. I know its a novice question. I am using the Home Edition.

Manipulate[Plot[{Sin[2 Pi/ax], cCos[2 Pi/bx]}, {x, 0, 4 Pi}, PlotStyle → {GrayLevel[0], GrayLevel[.5]}, PlotRange → {-4 Pi/2, 4 Pi/2}, AspectRatio → 1], {{a, 2 Pi, “Period for Sine”}, .1, 4}, {{b, 2 Pi, “Period for Cosine”}, .1, 5}, {{c, 2 Pi, “Amplitude for Cosine”}, .1, 5}]

2

Hey Scott,

You either need a multiplication symbol or a space between the expression and the constant you multiply the expression with. In the code below I inserted spaces.

Manipulate[
 Plot[{Sin[2 Pi/a x], c Cos[2 Pi/b x]}, {x, 0, 4 Pi}, 
  PlotStyle -> {GrayLevel[0], GrayLevel[.5]}, 
  PlotRange -> {-4 Pi/2, 4 Pi/2}, 
  AspectRatio -> 1], {{a, 2 Pi, "Period for Sine"}, .1, 
  4}, {{b, 2 Pi, "Period for Cosine"}, .1, 
  5}, {{c, 2 Pi, "Amplitude for Cosine"}, .1, 5}]

Hope it helps.

3

Thanks. That was it. Typing this in can be deceiving because the cursor acted like there was already a space. Obviously not.