I used the brute force method as you said, however, it still seems like the two regions are separated by a line (maybe a little curve). Also, I get the same plot by using the Matlab function
fsolve. It's a little strange.
Quote:
Originally Posted by magdon
The hypothesis is not a line. The hypothesis is a region on the 2dimensional space that is +1 and the complement of that region is 1. The boundary that separates the +1 from the 1 region is a line for linear classification. For nonlinear classification the boundary is something else. In either case you can identify the boundary by identifying the regions which are +1 and the regions which are 1.
For nonlinear boundary, there may be more than one x2 for a given x1 or even no x2 for a given x1. This is why the brute force approach is the simplest for identifying the boundary.
