[?] Plot a 2D Graph with two variables?

Questions
1

sin2xcos²t where x has 3 values [?/4,?/6,?/12,] and t ranges from 0 to 3.
The graph which is required is attached below.

2

Plot[Sin[2 [Pi] {1/4, 1/6, 1/12}] Cos[t]^2, {t, 0, 3}]

3

$Version
(* 11.3.0 for Microsoft Windows (64-bit) (March 7, 2018) *)

 f[x_, t_] := Sin[2 x]*Cos[t]^2;

 Plot[f[#, t] & /@ {Pi/4, Pi/6, Pi/12} // Evaluate, {t, 0, 3}, PlotStyle -> {Black, {Black, Dashed}, {Black, 
 AbsoluteDashing[{2, 4}]}}, PlotLegends -> LineLegend[{"\!\(\*FractionBox[\(Pi\), \(4\)]\)", "\!\(\*FractionBox[\(Pi\), \(6\)]\)", 
 "\!\(\*FractionBox[\(Pi\), \(12\)]\)"}, LegendLabel -> "Label", LegendFunction -> (Framed[#, RoundingRadius -> 5] &), 
 LegendMargins -> 5], AxesLabel -> {"\!\(\*FractionBox[\(Gt\), \(Pi\)]\)", "CAB"}]

.

Bez 44444tytułu.png
Bez 44444tytułu.png1029×396 11.4 KB

Regards,MI

4

Thank you very much for your kind reply sir.

5

Thank you very much for your kind reply sir.You have really explained with details.