Construct the 4 by 4 matrix (representing an affine transformation in homogeneous coordinates) T that rotates clockwise (as viewed toward the origin) through angle A about the pole (unit vector) u = (a,a,0) for a = sqrt(2)/2. Let C = cos(A) and S = sin(A), and use symbols a, C, and S in your expression for T.

Hint: start with a transformation that maps u to one of the axes; rotate about that axis; then invert the first transformation.