Let T1 be the linear transformation corresponding to a rotation by an angle of θ1 about x-axis in R3, and T2 the linear transformation corresponding to a rotation by an angle of θ2 about z-axis.
a) Compute the standard matrices for T1 and T2.
b) for what values of θ1 and θ2 does T2.T1 = T1.T2?
[ HINT: You will need to consider the different possible cases, and to know a little geometry.]