1. What is a normal?
A normal to a tangent to a curve is a straight line passing through the point of contact of the tangent and the curve at right angles to the tangent.
2. What is the relationship between the gradients of a tangent and the normal to the tangent?
The gradients are connected by the relation m1m2 = -1
This equation can also be written m1 = 1/ m2
So if the gradient of the tangent is 0.25, the gradient of the normal will be -4
