Simplification

Since Maxima does not perform Singular value decomposition for matrices with symbolic entries, I computed the SVD of the x-shear matrix (computer graphics) by hand and tried to use maxima to verify the result. The matrix is matrix([1, x], [0, 1]). As recorded in the uploaded xMaxima console file I entered the U, S and VT and tried to evaluate U.S.VT which should evaluate to the shear matrix but got a matrix with complicated entries. Trying a smaller step I computed u11^2+u21^2, i.e. the length of the first column which is supposed to be 1 since U is an orthonormal matrix, but even that xMaxima was unable to verify.