单项选择题
已知由方程siny+xey=0,确定y是x的函数,则dy/dx的值是:()
A.-(ey+cosy)/xey B.-ey/cosy C.-ey/(cosy+xey) D.-cosy/xey
A.-1/f″(t) B.1/[f″(t)]2 C.-1/[f″(t)]2 D.1/f″(t)
A.e B.e C.1 D.2