Waves can be model by linear combinations of the type [math]asin\left(x\right)+bcos\left(x\right)[/math].[br]Furthermore, any of these linear combinations admit an alternative expression that shifts a[br]sine function, [math]Asin(x+\alpha)[/math].[br]Try to find the relation between values [i]A[/i], [i]a[/i], [i]b[/i] and [math]\alpha[/math].[br][br]Students work in pairs (students A and B).[br][br]1) Student A shuffles values [i]a[/i] and [i]b[/i], pushing the red button. A new wave function would appear in the graphic view.[br]2) Student B manipulates sliders to select values [i]A[/i] and [math]\alpha[/math], so the blue graphic superimposes the red one.[br]3) Student A tries to find a numerical relation in the spreadsheet.[br]4) Students A and B interchange roles and repeat steps (1) to (3) a number of times.[br]5) Students write down conclusions about the observed numerical and algebraic relations.