f'(x)=5x^(2/3)+(10/3)x
f''(x)=(10/3)x^(-1/3)+10/3=0
x^(-1/3)=-1
x=-1
x^(-1/3)是减函数,且x≠0
所以x0
-1
确定f(X)=3x^5/3+5/3x^2的凹凸区间与拐点
f'(x)=5x^(2/3)+(10/3)x
f''(x)=(10/3)x^(-1/3)+10/3=0
x^(-1/3)=-1
x=-1
x^(-1/3)是减函数,且x≠0
所以x0
-1