计算:(1/2x+1/3y)^2

问题描述:

计算:(1/2x+1/3y)^2

(1/2x+1/3y)^2=(1/4)x² + (1/3)xy +(1/9)y²

原式=(x/2+y/3)^2
=x^2/4+2*x/2*y/3+y^2/9
=x^2/4+xy/3+y^2/9