1> help bisection
error: help: `bisection' not found


1> help bisection
`bisection' is a function from the file C:\Documents and Settings\rudiger.achilles\desktop\bisection.m

BISECTION Trova uno zero di una funzione.
   ZERO=BISECTION(FUN,A,B,TOL,NMAX) approssima uno
   zero della funzione FUN nell'intervallo [A,B] con
   il metodo di bisezione. FUN accetta come input uno
   scalare reale x e restituisce uno scalare reale.
   Se la ricerca dello zero di FUN fallisce, il
   programma restituisce un messaggio d'errore.
   FUN puo' essere una inline function, una anonymous
   function od una function definita in un M-file.

   ZERO=BISECTION(FUN,A,B,TOL,NMAX,P1,P2,...) passa
   i parametri P1, P2,... alla funzione
   FUN(X,P1,P2,...).

   [ZERO,RES,NITER]= BISECTION(FUN,...) restituisce
   il valore del residuo RES in ZERO ed il numero di
   iterazioni effettuate per calcolare il valore ZERO.

Additional help for built-in functions and operators is
available in the on-line version of the manual.  Use the command
`doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at http://www.octave.org and via the help@octave.org
mailing list.


2> f = inline('p*V.^3+a*N^2*V-a*b*N^3-p*N*V.^V.^2-1.3806488e-23*N*T*V.^2','V','a','b','p','N','T');


3> plot([0,0.1], feval(f,[0,0.1],0.401,42.7e-6,3.5e7,1e3,300));


4> grid on


5> f
f =

f(V, a, b, p, N, T) = p*V.^3+a*N^2*V-a*b*N^3-p*N*V.^V.^2-1.3806488e-23*N*T*V.^2



6> f = inline('p*V.^3+a*N^2*V-a*b*N^3-p*N*V.^2-1.3806488e-23*N*T*V.^2','V','a','b','p','N','T');


7> plot([0,0.1], feval(f,[0,0.1],0.401,42.7e-6,3.5e7,1e3,300));


8> f = inline('p*V.^3+a*N^2*V-a*b*N^3-p*N*V.^2*b-1.3806488e-23*N*T*V.^2','V','a','b','p','N','T');


9> plot([0,0.1], feval(f,[0,0.1],0.401,42.7e-6,3.5e7,1e3,300));


10> grid on


11> a = 0.02; b = 0.04;


12> tol = 5e-7
tol = 5.0000e-007


13> nmin = ceil(log2((b-a)/tol))) - 1
parse error:

  syntax error

>>> nmin = ceil(log2((b-a)/tol))) - 1
                                ^



13> nmin = ceil(log2((b-a)/tol)) - 1
nmin =  15


14> [z, res, iter] = bisection(f, a, b, tol, 100, 0.401,42.7e-6,3.5e7,1e3,300)
error:  Il segno della funzione agli estremi dell'intervallo [A,B] deve essere diverso
error: called from:
error:   C:\Documents and Settings\rudiger.achilles\desktop\bisection.m at line 24, column 3


14> feval(f, a, 0.401,42.7e-6,3.5e7,1e3,300)
ans = -9420.5


15> feval(f, b, 0.401,42.7e-6,3.5e7,1e3,300)
ans = -1233.9


16> plot([0.02,0.04], feval(f,[0.02,0.04],0.401,42.7e-6,3.5e7,1e3,300));


17> plot([0.04,0.06], feval(f,[0.04,0.06],0.401,42.7e-6,3.5e7,1e3,300));


18> grid on


19> a = 0.040; b = 0.044;


20> [z, res, iter] = bisection(f, a, b, tol, 100, 0.401,42.7e-6,3.5e7,1e3,300)
z =  0.042700
res = -0.13618
iter =  12


21> nmin = ceil(log2((b-a)/tol)) - 1
nmin =  12


22> printf('V = %.6f metri cubi = %.3f litri \n', z, 1000*z)
V = 0.042700 metri cubi = 42.700 litri 


23> printf('V = %.6f metri cubi = %.3f litri', z, 1000*z)
V = 0.042700 metri cubi = 42.700 litri

24> printf('\n V = %.6f metri cubi = %.3f litri \n', z, 1000*z)

 V = 0.042700 metri cubi = 42.700 litri 


25> p = 3.5e7; a = 0.401; b = 42.7e-6; k = 1.3806488e-23; N = 1000; T =300;


26> q = [p, -p*N*b-k*N*T, a*N^2, -a*b*N^3];


27> roots(q)
ans =

   0.00000 + 0.10704i
   0.00000 - 0.10704i
   0.04270 + 0.00000i



28> quit