Question

Question 85 (ii)

Expand the following, using suitable identities.

$(x^{2}y-x{y}^2{)}^2$

Answer 1

We have,
$(x^{2}y-x{y}^2{)}^2=(x^{2}y{)}^2+(x{y}^2{)}^2-2x^{2}y\times x{y}^2$
$=x^4{y}^2+x^2{y}^4-2x^3{y}^3$ [using the identity, $(a-b{)}^2=a^2+b^2-2ab$]