高数不懂了,f(x+y,y/x)=x2+y2,求(x,y)
高数:已知f(x+y,y)=x^2+y^2,求f(x,y)
我做对了吗.x2(x-y)+y2(y-x)= x2(x-y)-y2(x-y)=x2-y2=(x+y)(x-y)
求函数f(x,y)=x2+xy+y2-6x-3y的极致
求函数f(x,y)=(x2+y2)2-2(x2-y2)的极值
0.5ln(x2+y2)=arctan(y/x),(x≠0,x≠y),求y’.
正整数x,y满足x2-y2=2xy,求x-y/x+y的值
整数x,y满足x2-y2=2xy,求x-y/x+y的值
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
x2-x-y2-y 解法:=(x2-y2)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y-1)
已知:x2+4x+y2-6y+13=0,求(x-2y)/(x²+y²)
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,