Find the point on the curve 2a2y = x3 – 3ax2 where the tangent is parallel to the x – axis.

Given:


The curve is 2a2y = x3 – 3ax2


Differentiating the above w.r.t x


2a2 = 3x3 – 1 – 32ax2 – 1


2a2 = 3x2 – 6ax


= ...(1)


= The Slope of the tangent = tan


Since, the tangent is parallel to x – axis


i.e,


= tan(0) = 0 ...(2)


tan(0) = 0


= The Slope of the tangent = tan


From (1) & (2),we get,


= 0


3x2 – 6ax = 0


3x(x – 2a) = 0


3x = 0 or (x – 2a) = 0


x = 0 or x = 2a


Substituting x = 0 or x = 2a in 2a2y = x3 – 3ax2,


when x = 0


2a2y = (0)3 – 3a(0)2


y = 0


when x = 2


2a2y = (2a)3 – 3a(2a)2


2a2y = 8a3 – 12a3


2a2y = – 4a3


y = – 2a


Thus, the required point is (0,0) & (2a, – 2a)


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