a) Substituting the coordinate (1,1) into the left hand side of the equation for C we obtain: (13) + 3*1 - 4(13)(13) = 1 + 3 - 4 = 0 = The right hand side of the equation, hence the equation is satisfied, and therefore (1,1) lies on C.
b) Differentiating implicity we find:
3x2 + 3dy/dx - 12x2y3 - 12x3y2dy/dx = 0
Rearranging yields:
3x2 - 12x2y3= (12x3y2 - 3)dy/dx
Hence dy/dx = (3x2 - 12x2y3/(12x3y2 - 3)
Which simplifies to
dy/dx = x2(1 - 4y3)/(4x3y2 - 1)
(An alternative expression can be obtained be moving the terms not involving dy/dx to the right hand side)