1.Sally____Beijing for Shanghai and_____there ever since.You can go and pay her a visit on your way to Hangzhou.（A)A.has left;worked B.left;worked C.has left;had worked D.left;has worked2.Did you have a good time last night?Yes,thank you.I apprecia

1.Sally____Beijing for Shanghai and_____there ever since.You can go and pay her a visit on your way to Hangzhou.（A)A.has left;worked B.left;worked C.has left;had worked D.left;has worked2.Did you have a good time last night?Yes,thank you.I apprecia f(1)+f(2)+f(3)+...+f(n)=n/n+1.求f(n) 如果函数f(x)满足：对任意实数a,b都有f(a+b)=f(a)f(b).且f(1)=1.则f(2)/f(1)+f(3)/f(2)…+f(2011)/f(2010)= f： %F. F f f 已知f(x)=3x的次方,求证1.f(a)×f(b)=f(a+b)2.f(a)÷f(b)=f(a-b) 设f是R+上的增函数,且f=f+f 1.求证f=f-f 2.若f=1且f＞f+2求a的范围 已知f(x+y)=f(x)+f(y)+xY(x+y),f’(0)=1.求f(x). 如果f(1)=3.f(2)=5.f(3)=7.f(4)=9.f(1/3)=1.f(1/4)=2.f(1/5)=3.则f(2012)-f(1/2015)等于多少 对于任意函数x、y,总有f(xy)-f(x)=f(y)(xy≠0）,求证1.f(1)=02.f(1/x)=-f(x)3.f(x/y)=f(x)-f(y) 如果函数y=f(x)的定义域为｛xlx>0}且f(x)为增函数,f(x)=f(x)+f(y)(1)求证：f(x除以y)=f(x)-f(y);(2)已知f(3)=1.且f(a)>f(a-1)+2,求a的取值范围等到十点 f(xy)=f(x)+f(y) 关于函数的1.已知f (x)在(－∞,＋∞)上是增函数,若a＋b≤0,则有A.f (a)+f (b) ≤－f (a) －f (b)B.f (a)+f (b)≥－f (a) －f (b)C.f (a)+f (b) ≤f (－a) ＋f (－b)D.f (a)+f (b)≥f (－a) ＋f (－b)2.如果f (1／x) =x/(1－x2) 对于任意整数x,y函数f(x)满足f(x+y)=f(x)+f(y)+xy+1.若f(1)=1.那么f(-8)等于? 1.对任意的正数函数f(x)满足f(xy)=f(x)+f(y),且f（8）=3,则f（2）=? 已知函数f(x)对一切x,y属于R都有f(x+y)=f(x)+f(y)+1.f(3)=a,f(12)=