Assume X, Y, Z, W and P are matrices of order 2 × n, 3 × k, 2 × p, n × 3 and p × k, respectively. Choose the correct answer in Exercises 21 and 22.
Q21. The restriction on n, k and p so that PY + WY will be defined are:
(A)
(B) k is arbitrary,
(C) p is arbitrary,
(D)
P and Y are of order and respectively.
PY will be defined only if k=3, i.e. order of PY is .
W and Y are of order and respectively.
WY is defined because the number of columns of W is equal to the number of rows of Y which is 3, i.e. the order of WY is
Matrices PY and WY can only be added if they both have same order i.e = implies p=n.
Thus, are restrictions on n, k and p so that PY + WY will be defined.
Option (A) is correct.