13．已知函数 $f(x)=\left\{\begin{array}{l}2 x^{3}, x<0, \\ -\tan x, 0 \leq x \leq \frac{\pi}{2},\end{array}\right.$ 则 $f\left(f\left(\frac{\pi}{4}\right)\right)=$
参考答案－2
2013 高考数学第 13 题答案解析
2013_退役省自主命题 (2013·文)
2013_退役省自主命题 (2013·文)
13．已知函数 $f(x)=\left\{\begin{array}{l}2 x^{3}, x<0, \\ -\tan x, 0 \leq x \leq \frac{\pi}{2},\end{array}\right.$ 则 $f\left(f\left(\frac{\pi}{4}\right)\right)=$