Question

at the centre of curature​

Answer 1

Answer:

In geometry, the center of curvature of a curve is found at a point that is at a distance from the curve equal to the radius of curvature lying on the normal vector. It is the point at infinity if the curvature is zero. The osculating circle to the curve is centered at the centre of curvature.

Explanation:

The centre of curvature is the centre of the sphere from which the mirror is cut. The midpoint of the aperture is the pole of the mirror.