dy/dx

The equation of a curve is a^2+4ab+b^2=3. Let (x1,y1) be a point on this curve. Find dy/dx, and hence show that the equation of the normal to the curve at(x1,y1) is a(2x1+y1)-b(x1+2y1)=2(x1^2-y1^2).

Find the coordinates of each point of the curve at which the normal passes through the origin.

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