y=(5-x)*x^(2/3)=5x^(2/3)-x^(5/3)
所以y'=5*(2/3)x^(2/3-1)-(5/3)*x^(5/3-1)
=(10/3)x^(-1/3)-(5/3)x^(2/3)
如果不懂,祝学习愉快!