设z=x2+√y,y=sinx，求全导数dz/dxd．

设z=x²+√y,y=sinx，求全导数dz/dxd．
【正确答案】：dz/dx=∂z/∂x•dx/dx+∂z/∂y•dy/dx=∂z/∂x+(∂z/∂y)(dy/dx) =2x+(1/2√y)cosx=2x+cos/2√sinx