分类：教育/科学-学习帮助
问题：y=根号下x求二阶导数的 
求二阶导数的
回答：y=根号下x 
y=√x =x^(1/2)
y′=(1/2)*x^(-1/2)
y″=(1/2)*(-1/2)*x^(-3/2)
=(-1/4)*[1/x^(3/2)]
=(-1/4)*[1/(x*√x)]
=(-1/4)*[√x/(x^2)]
=-√x/(4x^2)