f(x+y)=f(x)+f(y)+2xy lim f(h)/h =0 h 趋向0 问f'（x) 和f(x)

f(x+y)=f(x)+f(y)+2xy f(xy)=f(x)+f(y),证明f(x/y)=f(x)-f(y) f(x+y)+f(xy-1)=f(x)f(y)+2f(n)表达式 f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y 已知f(x+y)=f(x)+f(y)+2xy,求f(0) f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! f(x+y,x-y)=2xy(x-y),求f(x,y) f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? f(xy,x-y)=x^2-xy+y^2.求f(x,y) y'=-2xy;求f(x). f(xy)=f(x)+f(y),f(2)=1,f(3)=? f(xy)=f(x)+f(y)且f(8)=3则f(2)= f(xy)=f(x)+f(y),f(8)=3,则f(根2)等于 f(xy)=f(x)+f(y),f(8)=3,求f(√2), f'(0)=1,f(x+y)=f(x)+f(y)+2xy,求f(x) f(x)满足f(x+y)+f(xy)=2f(x)f(y)求函数的奇偶性 导数：f(x+y)=f(x)f(y),且f'(o)=1,求f'(x)f(x+y)=f(x)f(y),且f'(o)=1,求f'(x)f(x+y)=f(x)+f(y)+2xy,且f'(o)存在,求f'(x) f(1+x)=af(x),且f'(0)=b,求f'(1) 设f(x+y,x-y)=x^2+xy,求f(x,y)