若a+b=-1/2,则2a^2+4ab+2b^2=?
问题描述:
若a+b=-1/2,则2a^2+4ab+2b^2=?
答
2a^2+4ab+2b^2=2(a^2+2ab+b^2)=2(a+b)^2=2*(-1/2)^2=2*1/4=1/2
若a+b=-1/2,则2a^2+4ab+2b^2=?
2a^2+4ab+2b^2=2(a^2+2ab+b^2)=2(a+b)^2=2*(-1/2)^2=2*1/4=1/2