更新时间2022-04-10 18:58:04
z = f( x , y ) = √x * sin(y/x)
∂z/∂y = √x * cos(y/x)/x;∂y/∂z= √x/cos(y/x);
∂z/∂x = sin(y/x)/(2√x) - √x * cos(y/x) * y/x^2 = [ x * sin(y/x) - 2y * cos(y/x) ]/( 2x√x);
∂y/∂x = ∂y/∂z * ∂z/∂x
= √x/cos(y/x) * [ x * sin(y/x) - 2y * cos(y/x) ]/( 2x√x)
= [ x * sin(y/x) - 2y * cos(y/x) ]/[ 2x * cos(y/x) ]
∂y/∂x|( 1,0 ) = [ 0 - 0 ]/[ 2 ] = 0 。