the function f given by f(x)=9*x^(2/3)+3x-6 has a relative minimum at x=?a.-8 b.-2^(1/3) c.-1
问题描述：
the function f given by f(x)=9*x^(2/3)+3x-6 has a relative minimum at x=?a.-8 b.-2^(1/3) c.-1
d.-1/8 e/0
the function f given by f(x)=9*x^(2/3)+3x-6 has a relative minimum at x=?
a.-8
b.-2^(1/3)
c.-1
d.-1/8
e.0
答
f(x)=9*x^(2/3)+3x-6 求导得f'(x)=9*6x^(-1/3)+3x=0=>x=-8,选a我本来选的也是a , 但答案上写的是e你题目中都定义有x^(2/3）了，所以x不可能为0