Question

(x+y)的平方加(x-y)的平方.简便计算？

Answer 1

(x+y)²+(x-y)²
=x²+y²+2xy+x²+y²-2xy
=2x²+2y²
数学辅导团为您解答,有错误请指正,,2,（x+y）²+（x-y）²=2x²+2y²,2,平方和的两倍,1,(x+y)2+(x-y )2=x2+2xy+y2+x2-2xy+y2=2(x2+y2),0,