I've got these three problems that I just can't work out. If someone could explain one or all of them, that would be fantastic

1) Find a formula for the Y(Nth derivative) for X^4+Y^4=A^4

^^^(Derivative of X with respect to Y)^^^

2) Suppose the curve X^4+aX^3+bX^2+cX+d has a tangent line with a formula y=2x+1 at x=0, and one with a formula y=2-3x at x=1. Find the values of a, b, c, and d.

3)Suppose that XY=C has a tangent line at point P.

a) Show that the midpoint of the line segment cut from this tangent line by the coordinate axes is P.

b) Show that the triangle formed always has the same area, no matter where P is located on the graph of the function.

You guys have yet to let me down, and I'm really counting on you this time! Thanks!