Show that the curves and touch each other.

If the two curve touch each other then the tangent at their intersecting point formed a angle of 0.

We have to find the intersecting point of these two curves.


xy = a2 and x2 + y2 = 2a2



x4 – 2a2x2 + a4 = 0


(x2 – a2) = 0


x = +a and -a


At x = a, y = a


At x = -a, y = -a



m1 at (a, a) = -1


m1 at (-a, -a) = -1



m2 at (a, a) = -1


m2 at (-a, -a) = -1


At (a, a)



θ = 0


At (-a, -a)



θ = 0


So, we can say that two curves touch each other because the angle between two tangent at their intersecting point is equal to 0.


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