part of question 2

three methods and chart

README.md

@@ -1,2 +1,25 @@
 # 02_roots_and_optimization
 Repository for homework 2
+
+Question 2
+'''matlab
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,fx,ea,iter]=falsepos(cat_cable,900,910,0.00001)
+'''
+'''matlab
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,fx,ea,iter]=bisect(cat_cable,908,909,0.00001)
+'''
+'''matlab
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,ea,iter]=mod_secant(cat_cable,900,910,0.00001)
+'''
+
+
+'''matlab
+| solver | initial guess(es) | ea | number of iterations|
+| --- | --- | --- | --- |
+|falsepos   | 900, 910 |  0.00001| 4 |
+|mod_secant | 900, 910 |  0.00001| 50 |
+|bisect     | 900, 910 |  0.00001| 17 |
+'''

bisect_cat.m

@@ -0,0 +1,2 @@
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,fx,ea,iter]=bisect(cat_cable,900,910,0.00001)

falsepos.m

@@ -23,7 +23,7 @@ while (1)
   xrold = xr;
   xr = (xl + xu)/2;
   % xr = (xl + xu)/2; % bisect method
-  xr=xu - (f_m(xu)*(xl-xu))/(f_m(xl)-f_m(xu)); % false position method
+  xr=xu - (func(xu)*(xl-xu))/(func(xl)-func(xu)); % false position method
   iter = iter + 1;
   if xr ~= 0,ea = abs((xr - xrold)/xr) * 100;end
   test = func(xl,varargin{:})*func(xr,varargin{:});

falsepos_cat.m

@@ -0,0 +1,2 @@
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,fx,ea,iter]=falsepos(cat_cable,900,910,0.00001)

mod_secant_cat.m

@@ -0,0 +1,2 @@
+cat_cable = @(T) -35+T/10.*cosh(10./T*30)+30-T/10;
+[root,ea,iter]=mod_secant(cat_cable,900,910,0.00001)