已知x>0,y>0,x+2y+2xy=8,求x+2y的最小值.x+2y+2xy=8≥2倍根号下2xy+2xy 令根号下xy=t,t≥0,则2t的平方+(2倍根号2)乘以t—8大于等于0,所以t大于等于根号—2倍根号2,小于等于根号2,又因为t大于0,所以t的
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![已知x>0,y>0,x+2y+2xy=8,求x+2y的最小值.x+2y+2xy=8≥2倍根号下2xy+2xy 令根号下xy=t,t≥0,则2t的平方+(2倍根号2)乘以t—8大于等于0,所以t大于等于根号—2倍根号2,小于等于根号2,又因为t大于0,所以t的](/uploads/image/z/1015664-32-4.jpg?t=%E5%B7%B2%E7%9F%A5x%3E0%2Cy%3E0%2Cx%2B2y%2B2xy%3D8%2C%E6%B1%82x%2B2y%E7%9A%84%E6%9C%80%E5%B0%8F%E5%80%BC.x%2B2y%2B2xy%3D8%E2%89%A52%E5%80%8D%E6%A0%B9%E5%8F%B7%E4%B8%8B2xy%2B2xy+%E4%BB%A4%E6%A0%B9%E5%8F%B7%E4%B8%8Bxy%3Dt%2Ct%E2%89%A50%2C%E5%88%992t%E7%9A%84%E5%B9%B3%E6%96%B9%2B%282%E5%80%8D%E6%A0%B9%E5%8F%B72%29%E4%B9%98%E4%BB%A5t%E2%80%948%E5%A4%A7%E4%BA%8E%E7%AD%89%E4%BA%8E0%2C%E6%89%80%E4%BB%A5t%E5%A4%A7%E4%BA%8E%E7%AD%89%E4%BA%8E%E6%A0%B9%E5%8F%B7%E2%80%942%E5%80%8D%E6%A0%B9%E5%8F%B72%EF%BC%8C%E5%B0%8F%E4%BA%8E%E7%AD%89%E4%BA%8E%E6%A0%B9%E5%8F%B72%EF%BC%8C%E5%8F%88%E5%9B%A0%E4%B8%BAt%E5%A4%A7%E4%BA%8E0%EF%BC%8C%E6%89%80%E4%BB%A5t%E7%9A%84)
已知x>0,y>0,x+2y+2xy=8,求x+2y的最小值.x+2y+2xy=8≥2倍根号下2xy+2xy 令根号下xy=t,t≥0,则2t的平方+(2倍根号2)乘以t—8大于等于0,所以t大于等于根号—2倍根号2,小于等于根号2,又因为t大于0,所以t的
已知x>0,y>0,x+2y+2xy=8,求x+2y的最小值.x+2y+2xy=8≥2倍根号下2xy+2xy 令根号下xy=t,t≥0,则
2t的平方+(2倍根号2)乘以t—8大于等于0,所以t大于等于根号—2倍根号2,小于等于根号2,又因为t大于0,所以t的最小值为0,所以x+2y的最小值为0.
跪求是哪儿错了,这题的正确答案是4
已知x>0,y>0,x+2y+2xy=8,求x+2y的最小值.x+2y+2xy=8≥2倍根号下2xy+2xy 令根号下xy=t,t≥0,则2t的平方+(2倍根号2)乘以t—8大于等于0,所以t大于等于根号—2倍根号2,小于等于根号2,又因为t大于0,所以t的
x+2y+2xy=8≥2倍根号下2xy+2xy
令2xy=t,t≥0,
则2√ t+t≤8
2√ t≤8-t
t≤8且4t≤64-16t+t²,t²-20t+64≥0,t≤4或t≥16
所以0≤t≤4
x+2y=8-t
x+2y的最小值是4
因为x+2y≥2倍根号2xy下,所以的x+2y最小值应该是2xy的最大值等于2,再乘2得4