A.maths Differentiation~

Find dy/dx of each of the following implicit functions:

1. √x + √y = 4
2. √(x+y) = x - y + 1
3. 2x^2 + √(xy) + y^2 = 10

Find d^2y/dx^2 of the following functions:

1. x^2 - xy + y^2 = 6
2. If y = (3x^2 + 4)/x , Show that x^2(d^2y/dx^2)+x(dy/dx) - y = 0