已知x>y>0,求证x+1/(x-y)x>=3

已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 已知x+y+z=1，求证x 已知x>0,y>0且x+y=1,求证根号(x+1/2)+根号(y+1/2) 已知x>y>0,xy=1,求证(x^2+y^2)/(x-y)≥2根号2 已知x,y∈R*,x+y=1,求证2/x+1/y≥3+2根号2 已知|3x-y|+|x+y|=0,求x-y除以x*y的值. 已知sin(x+y)=1,求证：tan(2x+y)+tany=0 已知sin(x+y)=1,求证:tan(2x+y)+tany=0 已知sin（x+y）=1,求证：tan（2x+3y）=tany 已知xyz属于R+,x+y+z=1,求证x^3/(y(1-y))+y^3/(z(1-z))+z^3/(x(1-x))大于 已知x,y,z满足xyz=1,求证x^3/(x+y)+y^3/(y+z)+z^3/(z+x)大于等于3 已知x,y,z都是正数,且xyz=1,求证：x^2/(y+z)+y^2/(x+z)+z^2/(x+y)≥3/2