复合函数

题1: 8．已知函数$f(x)=\left\{\begin{array}{c}-x{e}^{x},x<0\\ ln(x+1),x\geqslant 0\end{arr

题2: 20．已知函数$f(x)=x^{2}+2x+a(a<0)$，若函数$y=f(f(x))$有三个零点，则$a=$___$\frac{-1-\sqrt{5}}{2}

题3: 19．已知函数$f(x)=-x^{2}+2x+a(a>0)$，若$f(f(x))$有三个零点，则$a=$___$\frac{\sqrt{5}+1}{2}$___

题4: 10．已知函数$f(x)=\left\{\begin{array}{l}\vert {{e^x}-1}\vert ,x\leqslant 1,\\ \frac

题5: 5．已知函数$f(x)=\left\{\begin{array}{l}{{2}^{x}+1,x\leqslant 0}\\ {\vert lo{g}_{2}x\

题6: 14．已知函数$f(x)=\left\{\begin{array}{l}x-\frac{1}{x},x<0,\\ x+\frac{1}{x},x>0.\end

题7: 3．已知函数$f(x)=\left\{{\left.\begin{array}{l}{\frac{1}{1-x},x<0}\\ {\vert {lnx}\ver

题8: 1．已知函数$f(x)$是$R$上的奇函数，当$x<0$时，$f(x)=4-2^{-x}$．若关于$x$的方程$f(f(x))=m$有且仅有两个不相等的实数解，

题9: 11．已知函数$f(x)=\left\{{\left.\begin{array}{l}{5{e^x}+1,x<0}\\ {\vert {{x^2}-6x+8}\

题10: 18．已知函数$f(x)=\left\{\begin{array}{l}x^{3}-x,x\leqslant 0\\ lnx,x>0\end{array}\r

题11: 13．若函数$f(x)$和$g(x)$的定义域都是$R$，且关于$x$的方程$f[g(x)]=x$有实数解，则下列式子中可以是$g[f(x)]$的是$($　　$

题12: 17．已知函数，若函数$y=f[f(x)]-\frac{3\pi }{2}$有5个零点，则实数$a$的取值范围是

题13: 15．已知函数$f(x)=\left\{{\left.\begin{array}{l}{ax+1,x\leqslant 0,}\\ {-\vert {{\log

题14: 9．已知函数$f(x)=\left\{{\left.\begin{array}{l}{\vert lg\vert x-1\vert \vert ,x\ne 1}

题15: 12．已知函数$f(x)=\left\{\begin{array}{l}{x^{2}-kx+1,x\leqslant 0}\\ {lo{g}_{2}x,x>0}

题16: 4．已知函数$f(x)=\left\{{\left.\begin{array}{l}{{e^x},x\leqslant 0}\\ {\vert {lnx}\ve

题17: 2．已知函数$f(x)=\left\{{\left.\begin{array}{l}{{e^x},x<0,}\\ {\vert lnx\vert ,x>0,}\

题18: 16．设函数$f(x)=x^{2}+2x$，$g(x)=\left\{{\left.\begin{array}{l}{x+\frac{1}{x},x>0,}\\

题19: 7．已知函数$f(x)=\left\{\begin{array}{l}2x-3,x>0,\\ {x}^{3}-3x+1,x\leqslant 0\end{arr