What is a mathmatic normal?

Question

what is a normal

Is it a line that is perpendicular to another line?

or is it the line perpendicular to the tangent line of a graph?

Help PLEASE!

Answer 1

Normal is just another way to say perpendicular. However, if you are asked about the line normal to a curve at a given point, what is meant is that the normal line will be perpendicular to the tangent at that specified point. You could also speak about two arbitrary curves being normal to each other; what this would mean is that the tangents to both curves at the point of intersection would be perpendicular to each other.