यदि P = {a, b, c} तथा Q = {r} है तो `P xx Q` एवं `Q xx P` ज्ञात कीजिए। `P xx Q = Q xx P` क्या है ?

Answer

`P xx Q = {(a, d), (b, d), (c, d)}`
`Q xx P = {(d, a), (d, b), (d, c)}`, `P xx Q + Q xx P`