Intersection Angle Two Curves:

If two curves intersect at an arbitrary point P, the angle of intersection of the provided curves is the angle in between tangents to the curves at P.

The angle of intersection, θ, of the two curves at an arbitrary point P is shown by the formula

 

Where m₁ and m₂ are the slopes of the curves to the provided curves at P.

Corollary: Two curves intersect orthogonally at P if

m₁ × m₂ = - 1

where m₁ and m₂ are the slopes of the curves to the provided curves at P.