加性函数是
f(x+y)=f(x)+f(y)f(x+y)=f(x)+f(y)f(x+y)=f(x)+f(y)对gcd(x.y)=1\gcd(x.y)=1gcd(x.y)=1
还是f(xy)=f(x)+f(y)f(xy)=f(x)+f(y)f(xy)=f(x)+f(y)对gcd(x.y)=1\gcd(x.y)=1gcd(x.y)=1
