x大于0,y大于0.z大于0.且x+y+z=1.求证,x分之1+y分之4+z分之9大于等于36

问题描述:

x大于0,y大于0.z大于0.且x+y+z=1.求证,x分之1+y分之4+z分之9大于等于36