\begin{array}{ll} \sin\pi x \quad\quad,x\in[0,2]\\ \dfrac{1}{2}f(x-2)\quad,x\in(2,+\infty) \end{array} \right.$,
改为选择题就比较完美了!
\begin{array}{ll} \sin\pi x \quad\quad,x\in[0,2]\\ \dfrac{1}{2}f(x-2)\quad,x\in(2,+\infty) \end{array} \right.$,则方程$f(x)=\dfrac{5}{4x}$的根的个数为
还可以这样改,避免了超越方程的根!(谢林老师提供)
\begin{array}{ll} 1-a|x-1| \quad\quad,x\in[0,2]\\ \dfrac{1}{2}f(x-2)\quad,x\in(2,+\infty) \end{array} \right.$,