I had a line, y=-1/2 x
I wanted to reflect everything onto the line so as you can see by my steps in the picture below(sorry, I dont know the coding) I first rotated the line theta degrees then projected everything to that line and rotated it back.
I think maybe my triangle for the values of theta are incorrect...this is right at the top. The problem also might be the way I am applying these matrices. To do this, I am correct if my first transformation starts on the left, my second would follow on the right and so on.
As you can see my matrix for the FIRST rotation was on the right hand side(This was the counter clockwise rotation, so the rotation matrix stays the same. The only thing that caused a change is my triangle because putting sin(theta) into the matrix would give me a negative sin, and the negatives would cancel out.[ This all refers to my first transformation matrix]
None the less, I cannot understand where I've gone wrong. Could someone help me understand why my martrices differs from the ones right at the bottom.