f(6)=1
令x=36,y=6
f(36/6)=f(36)-f(6)
f(6)=f(36)-f(6)
2f(6)=f(36)
f(36)=2
f(x+3)-f(1/x)0,满足f(x/y)=f(x)-f(y)
f[(x+3)/(1/x)]0
所以x^2+3x
f(6)=1
令x=36,y=6
f(36/6)=f(36)-f(6)
f(6)=f(36)-f(6)
2f(6)=f(36)
f(36)=2
f(x+3)-f(1/x)0,满足f(x/y)=f(x)-f(y)
f[(x+3)/(1/x)]0
所以x^2+3x