The simplest minimization problems are those in which there is only a single variable. Later we will see how minimization in many dimensional space can be broken down into a series of 1-D `line' minimizations.
One major advantage of 1-D over multi-D minimization is that it is easy to define a region in which we are sure a minima must exist.
If we can find three points a, b and c with a<b<c and
then there must exist at least one minimum point in the
interval 
. The points a , b and c are said to
bracket the minimum.