Find the point on the curve at which the tangents are parallel to y – axis

Since the tangent is parallel to y–axis, its slope is not defined, then the normal is parallel to x–axis whose The Slope is zero.


i.e., = 0


= 0


= 0


y = 0


Substituting y = 0 in = 1,


= 1


x2 = 9


x = ±3


Thus, the required point is (3,0) & ( – 3,0)


19