简单的向量运算B(x,y,z)=(x,y*z)(,)是点积y*z是叉积用B(x,x,z)=0推出 B(x,y,z)=-B
已知X+Y+Z=a,XY+YZ+XZ=b,求X*X+Y*Y+Z*Z的值
(x+y-z)(x-y+z)=
已知a(y-z)+b(z-x)+c(x-y)=0求证(cy-bz)/y-z=(az-cx)/z-x=(bx-ay)/x-
X+Y+Z=?
已知x、y、z均为实数,若X+Y+Z≠0,a=X/X+Y,b=Y/Z+X,c=Z/X+Y,求a/a+1,b/b+1,c/
已知a-b:x=b-c:y=c-a:z≠0,求x+y+z的值
已知(a-b)/x=(b-c)/y=(c-a)/z不等于0,求x+y+z的值
x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y----
已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz
y+z÷x=Z+X÷y=X+Y÷z,X+Y+Z不等0求X+Y-Z÷X+Y+z值
x分之y+z=y分之z+x=z分之x+y(x+y+z不等于0),求x+y+z分之x+y-z
已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)