若x,y属于r且1/(x+2)+1/(y+1)=1,则x+2y的最小值为

求x+2y的最小值我们可以先求x+2+2(y+1)的最小值因为x+2+2(y+1)=(x+2y)+41/(x+2)+1/(y+1)=11乘以任何数都等于1[1/(x+2)+1/(y+1)][(x+2)+2(y+1)]=1+2+(x+2)/(y+1)+2(y+1)/(x+2)均值不等式≥3+2√2x+2+2(y+1)的最小值为...