I would like to use fuzzy logic to solve a third degree polynomial equation. The equation looks like y=2*x^3 + 1.2*x^2 -x in the range -1.4<x<0.8
First, I would like to start by using 3 or 4 rules then I will add 2 or 3 rules to increase the accuracy.
I started to divide the main graph into 3 straight lines. The first one -1.4<x<0.7, the second one -0.7<x<0.3 and the last one 0.3<x<0.8.
I was wondering what the input and the output membership functions should be, and if anyone can propose a rule. I appreciate any help to solve this problem