y≥0,x^2 +y^2 =3,u=(y+1)/(x+3) ,求u的最值.

y≥0,x^2 +y^2 =3,u=(y+1)/(x+3) ,求u的最值. 帮忙证明个高数题u=x^2*y^2/(x+y),求证 x*u(x)+y*u(y)=3u 函数u^2lnv,u=x/y,v=3x-2y 假设集合U={(x,y)|x∈R,y∈R },A={(x,y)|2x-y+m>0},B={(x,y)|x+y-n x,y>0,且x+2y=1,u=(x+1/x)(y+1/(4y)最小值是: x>=0,y>=0.2x+y=6,则u=4x^2+3xy+y^2-6x-3y最小值 已知实数x,y满足4x+3y>=0,则u=x^2+4x+y^2-2y的最小值为? x,y大于等于0 x+2y=1 U=x+3y² 求U取值范围 已知实数XY满足4X+3Y≥0,则U=X平方+Y平方+4X-2Y最小值? 若x+y-1==0,y>=-1.且u=x^2+y^2-4x-4y+8,则u的最小值? int x=0,y=1,u=2,v=3,w; w=x>y?x:u>v?u:v; system out.println (w) 已知x,y∈R*,x+y=xy,求u=x+2y最小值 四元一次方程的解法y+z+u=1z+u+x=2u+x+y=3x+y+z=4 x和y趋于0,求(x^2+y^x)*sin(2/(x^2+y^2))第二题,z=ln(uv),u=3x-2y,v=3x+2y,求对y的偏导数 证明函数u(x,y)=f(y/x^2)*x^n满足x*（∂u/∂x)+2y*(∂u/∂y)=nu du(x,y)=2xycos(x^2y)dx+x^2cos(x^y)dy,求u(x,y) 全集u={(x,y)|x属于实数,y属于实数},集合m={(x,y)|y-3/x-2=1},集合n=[(x,y)|y不等于x+1,那[u(MUN）等于 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2