f(x)=1/3x³-(2a+1)x²+3a(a+2)x+1
f(x)′=3*1/3x²-2(2a+1)x+3a(a+2)
f(x)′=x²-2(2a+1)x+3a(a+2)
当函数y=f'(x)在(0,4)上有唯一的零点时
4=3a(a+2)
4=3(a²+2a)
3(a²+2a+1)=4+3
(a+1)²=7/3
求出a的取值范围
f(x)=1/3x³-(2a+1)x²+3a(a+2)x+1
f(x)′=3*1/3x²-2(2a+1)x+3a(a+2)
f(x)′=x²-2(2a+1)x+3a(a+2)
当函数y=f'(x)在(0,4)上有唯一的零点时
4=3a(a+2)
4=3(a²+2a)
3(a²+2a+1)=4+3
(a+1)²=7/3
求出a的取值范围