Question

问下数学第二小题 f(6)不知该怎么用

Answer 1

(1)∵对一切x,y>0,满足f(x/y)=f(x)-f(y),

f( 1)=f(1/1)=f(1)-f(1)=0；

(2) f(xy)

=f[x/(1/y)]

=f(x)-f(1/y)

=f(x)-[f(1)-f(y)]

=f(x)+f(y)

故f(x+3)-f(1/3)

=f[(x+3)/(1/3)]

=f[3(x+3)]