14.已知f(x)=$\left\{\begin{array}{l}{0(x>0)}\\{-1(x=0)}\\{2x-3(x<0)}\end{array}\right.$,则f[f(3)]=( )
| A. | 0 | B. | -1 | C. | 5 | D. | -5 |
13.已知奇函数f(x),当x<0时,f(x)=x+$\frac{1}{x}$,则f(1)=( )
0 232982 232990 232996 233000 233006 233008 233012 233018 233020 233026 233032 233036 233038 233042 233048 233050 233056 233060 233062 233066 233068 233072 233074 233076 233077 233078 233080 233081 233082 233084 233086 233090 233092 233096 233098 233102 233108 233110 233116 233120 233122 233126 233132 233138 233140 233146 233150 233152 233158 233162 233168 233176 266669
| A. | 1 | B. | 2 | C. | -1 | D. | -2 |