just a suggestion for all matrix transformation Qs
instead of remembering all base vectors ,..do this
suppose its a stretch with x-axis invariant and stretch factor 2
so..
always transform 2 points
1st --> 1,0
2nd --> 0,1
1,0 to 1,0 (strect of scale factor 2 but x-axis invariant)
0,1 to 0,2 ( ll )
put that as a matrix
(1 0)
(0 2) (put only the cordinates of the image, in vertical form)
this can be done for all transformations
we do it this way, its easier than remembering all..
for complicated ones use
(a b) * (ox1 ox2) = (ix1 ix2)
(c d) (oy1 oy2) (iy1 iy2)
ox/y = object cordinates
ix/y = image cordinated
