I have a sinusoid curve in an euclidian orthonormal plane [OX,OY].
the equation of the curve is y=a sin x.
Now, I want to get the equation of the curve when I rotate it by an angle with respect to the (ox) axis like it is shown in the figure submitted.
To do that,I'll define tehe vectorial euclidian rotation :in an oriented vectorial euclidian plan, a vectorial rotation is simply defined by its angle . Its matrix in an orthonormal direct basis is :
In another way, a vector (x,y) has as image the vector (x',y') that can be calculated like that :
then we have :
as we have
, then we have
the problem is that I must write in function of .
Thank you for reading me. I'll be vey glad if you can help me