In a data–processing pipeline, a column vector of 5 measurements is first transformed by a matrix T1 of order 6×5, then by a matrix T2 of order 4×6, and finally by a matrix T3 of order 5×4.
(a) For each of the following compositions, state whether it is possible. Whenever it is possible, write the order of the resulting matrix (do not perform any numerical multiplication):
(i) T2T1(ii) T3T2(iii) T3T2T1(iv) T1T2.
(b) The engineer wishes to replace the three–step process by a single matrix that acts directly on the original 5×1 data vector and produces the same final output as T3T2T1. Explain whether this is possible and, if so, state the order of that single matrix.
(c) Justify why the composition T1T3 is not meaningful in this context, even though T1 and T3 are individually defined matrices.