Matlab giai tich

GIẢI TÍCH NHÓM 1 function n1b1 % chuong trinh ve parabol elliptic a=input(''''nhap so a= ''''); b=input(''''nhap so b= ''''); [x,y]=meshgrid( 10 05 10); z=x ^2/a+y ^2/b; % lenh for o duoi de cat got do thi cho de[.]

u=input('nhap ham u(x,y)= ');

disp(['dao ham rieng theo x cap 10 tai (1,2) la: ' num2str(subs(diff(u,10,x) ,[x y],[1 2]))])

%lenh diff la dao ham

% lenh subs la thay x va y bang so x0 va y0

end

function n1b3

clc

syms x y real

f=input('nhap ham f(x,y)= ');

[a b]=solve([char(diff(f,'x')) '=0'],[char(diff(f,'y')) '=0']); % giai dao ham cap 1

sA=eval(A);sB=eval(B);sC=eval(C); %tim A,B,C

delta=(sA*sC-sB^2); %tinh delta

elseif sA < 0 % A > 0 la cuc dai

cd=[cd;a(i) b(i)]; zcd=[zcd;eval(f)];

i=1+i;

else

a(i)=[];b(i)=[];

n=n-1;

f=char(f);f=strrep(f,'^','.^');f=strrep(f,'*','.*');f=eval(f);

else % khong co cuc tri

disp('f khong co cuc tri chat, con co cuc tri ko chat hay khong thi chiu :))' )

set(surf(x,y,z),'facecolor','r','edgecolor','non')

text(cd(i,1),cd(i,2),zcd(i)+.1,['cuc dai (' num2str(cd(i,1)) ',' num2str(cd(i,2)) ','

set(surf(x,y,z),'facecolor','r','edgecolor','non')

text(ct(i,1),ct(i,2),zct(i)-.1,['cuc tieu (' num2str(ct(i,1)) ',' num2str(ct(i,2)) ','

end

end

end

function n1b5

[x,y]=meshgrid(-sqrt(3):.05:sqrt(3)); % tao luoi

z=sqrt(4-x.^2-y.^2); % mat tren

z2=-sqrt(4-x.^2-y.^2)+2; % mat duoi

for i=1:length(x) % vong lap loai bo cac diem nam ngoai mien giao nhau

set(surf(x,y,z2),'facecolor','b','edgecolor','non','facealpha',.3) % ve mat duoi

pcolor(x,y,z2) % ve hinh chieu

hold off

rotate3d on

syms x y phi real

z=sqrt(4-x^2-y^2); z2=-sqrt(4-x^2-y^2)+2;

x=2*r*cos(phi);y=2*r*sin(phi); % dat x,y theo toa do truc

z=eval(z);z2=eval(z2); % cap nhat bien moi cho x va y

V=int(int(4*r*(z-z2),'r',0,sqrt(3/4)),'phi',0,2*pi); %tinh tich phan kep

g=eval(f); %thay x vao f

g=g*sqrt(1+diff(x,'y')^2); % tinh tich phan duong loai 1

l=int(g,'y',-1,1); % tinh tich phan

n=[diff(f,'x') diff(f,'y') diff(f,'z')];

n=n/sqrt(diff(f,'x')^2 + diff(f,'y')^2 + diff(f,'z')^2); % tinh vector don vi cua vector phap

%phuong phap tinh la phuong phap stokes

p=(diff(R,'y')-diff(Q,'z'))*n(1,1);

q=(diff(P,'z')-diff(R,'x'))*n(1,2);

r=(diff(Q,'x')-diff(P,'y'))*n(1,3);

z=y^2;

f=(eval(p)+eval(q)+eval(r))*sqrt(1+diff(z,'x')^2+diff(z,'y')^2);

% da chuyen ve tich phan mat loai 1

syms r phi real

x=r*cos(phi);y=r*sin(phi); % chuyen sang phuong phap truc toa do

f=eval(f);

S=int(int(f*r,'r',0,1),'phi',0,2*pi); %tinh tich phan

S=double(S);

disp(['Tich phan can tinh la: I= ' num2str(S)])

% ve vector phap tai M0

disp('nhap diem M0 thuoc mat z=y^2 va x^2+y^2 <= 1 ')

disp('vidu M(0,1,1), thi ta nhap: 0,1,1')

m=input('M0= ','s');

m=str2num(m);

x=m(1,1);y=m(1,2);z=m(1,3);

n=eval(n);% the toa do diem vao vector

title(['mat z=y^2 nam trong hinh tru x^2+y^2=1 ' 'Va phap vector tai diem M0(' num2str(x)

',' num2str(y) ',' num2str(z) ')']) % tao tieu de

%bat dau ve vector phap

% co nhieu cach ve ban co the dung ham tu viet de ve

% nhung o day toi se ve bang ham thu viet cua matlab rat don gian

%trong do: 0,0,0 la toa do tam

% a,b,c lan luoc la ban kinh truc Ox, Oy, Oz

function n2b2

syms x y z real

f=input('nhap ham z(x,y)= ');

disp('nhap lan luoc toa do M0 thuoc z(x,y)')

x0=input('x0= ');y0=input('y0= ');z0=input('z0= ');

f1=f-z; %chuyen thanh f(x,y,z)=0

n=[ diff(f1,'x') diff(f1,'y') diff(f1,'z')]; %tinh dao ham

n1=subs(n,[x y z],[x0 y0 z0]); n1=double(n1); %tim vector gradian

f1=n1(1,1)*(x-x0)+n1(1,2)*(y-y0)+n1(1,3)*(z-z0); %mat tiep tuyen

disp(['phuonh trinh mat tiep tuyen la: ' char(f1) ' = 0' ])

disp('phuong trinh phap tuyen la: ')

% ve duong thang phap tuyen

[x y f]=loai(x,y,f); %loai bo cac diem bat dinh

set(surf(x,y,f),'facecolor','b','edgecolor','non','facealpha',.3)

%ve mat tiep tuyen

f=input('nhap ham f(x,y)= ');

disp('nhap a b cua ellip x^2/a+y^2/b=1')

Lxx=diff(Lx,'x');Lyy=diff(Ly,'y');Lxy=diff(Lx,'y'); %dao ham cap 2

phix=diff(phi,'x');phiy=diff(phi,'y'); %dao ham dieu kien

for i=1:length(m) %xet cuc dai, cuc tieu

if m(i)==inf || n(i)==inf || l(i)==inf

end

hold off

rotate3d on

end

%loai cac diem bat dinh

function [x y f]=khu(x,y,f) % chuong trinh loai bo cac diem khong ton tai cua ham f

function n2b4

syms x y real

warning off

y1=input('nhap ham y1(x)= ');

y2=input('nhap ham y2(x)= ');

f=input('nhap ham tinh tich phan f(x,y)= ');

if double(subs((y1-y2),'x',(n(1)+n(2))/2)) > 0 % neu y1 nam tren y2

I=int(int(f,'y',y2,y1),'x',n(1),n(2));

else % neu y2 nam tren y1

I=int(int(f,'y',y1,y2),'x',n(1),n(2));

% ve duong giao tuyen

n=[diff(f,'x') diff(f,'y') diff(f,'z')];

n=n/sqrt(diff(f,'x')^2 + diff(f,'y')^2 + diff(f,'z')^2); % tinh vector don vi cua vector phap

%phuong phap tinh la phuong phap stokes

p=(diff(R,'y')-diff(Q,'z'))*n(1,1);

q=(diff(P,'z')-diff(R,'x'))*n(1,2);

r=(diff(Q,'x')-diff(P,'y'))*n(1,3);

z=2-2*x;

% chuyen ve tich phan mat loai 1

f=(eval(p)+eval(q)+eval(r))*sqrt(1+diff(z,'x')^2+diff(z,'y')^2);

%tinh tich phan

syms r phi real

x=r*cos(phi);y=r*sin(phi); % chuyen sang phuong phap truc toa do

f=eval(f);

S=int(int(f*r,'r',0,sqrt(3)),'phi',0,2*pi); %tinh tich phan

S=double(S);

disp(['Tich phan can tinh la: I= ' num2str(S)])

% ve vector phap tai M0

disp('nhap diem M0 thuoc mat 2*x+z=2 va z >= x^2+y^2 ')

disp('vidu M(0,-1,2), thi ta nhap: 0,-1,2')

m=input('M0= ','s');

m=str2num(m);

x=m(1,1);y=m(1,2);z=m(1,3);

n=eval(n);% the toa do diem vao vector

title(['mat z=y^2 nam trong hinh tru x^2+y^2=1 ' 'Va phap vector tai diem M0(' num2str(x)

',' num2str(y) ',' num2str(z) ')']) % tao tieu de

%bat dau ve vector phap

f=input('nhap ham f(u)= ');

u=input('nhap ham u(x,y)= ');

disp('phap lan luoc cac toa do cua M0:')

x0=input('x0= ');

y0=input('y0= ');

f=eval(f); %thay u(x,y) vao f(u)

c=subs(f,[x y],[x0 y0]); %tinh f tai M0

text(x0,y0,c+.2,['M0 (' num2str(x0) ',' num2str(y0) ',' num2str(a) ')'])

syms x y lamda real

f=input('nhap ham f(x,y)= ');

disp('nhap parabol y(x) vd: y=6+4*x^2 ')

[l m n]=solve(Lx,Ly,phi-y,'x','y','lamda');

%giai he dao ham cap 1 voi: l <=> lamda , m <=> x , n <=> y

m=double(m); m(abs(imag(m))>0.0000000001)=inf;m=m-imag(m)*1i; %loai so phuc

n=double(n); n(abs(imag(n))>0.0000000001)=inf;n=n-imag(n)*1i;

l=double(l); l(abs(imag(l))>0.0000000001)=inf;l=l-imag(l)*1i;

Lxx=diff(Lx,'x');Lyy=diff(Ly,'y');Lxy=diff(Lx,'y'); %dao ham cap 2

phix=diff(phi-y,'x');phiy=diff(phi-y,'y'); %dao ham dieu kien

k=0;

for i=1:length(m) %xet cuc dai, cuc tieu

if m(i)==inf || n(i)==inf || l(i)==inf

set(surf(x,y,z),'facecolor','b','edgecolor','non','facealpha',.2)

%loai cac diem bat dinh

function [x y f]=khu(x,y,f) % chuong trinh loai bo cac diem khong ton tai cua ham f

x1=input('nhap ham x1(y)= ');

x2=input('nhap ham x2(y)= ');

f=input('nhap ham tinh tich phan f(x,y)= ');

%ve giao tuyen

n=[diff(f,'x') diff(f,'y') diff(f,'z')];

g=diff(P,'x')+diff(Q,'y')+diff(R,'z');

x=p*cos(phi)*sin(t);

y=p*sin(t)*sin(phi);

z=p*cos(t);

g=eval(g);

V=int(int(int(g*p^2*sin(t),'p',0,2),'t',0,pi/2),'phi',0,2*pi);

% ta tru cho tich phan mat duoi mat duoi huong xuong oz => V=V+S

n=eval(n);% the toa do diem vao vector

%bat dau ve vector phap

disp('ban mun ve Hyperboloid 1 tang hay 2 tang')

disp('neu mun ve 1 tang thi nhap: 1')

d=input('1 hay 2: ','s');d=str2double(d);

if d==1

d=-1;

disp('nhap cac so a b c thuoc x^2/a^2+y^2/b^2-z^2/c^2=1')

disp('nen nhap cac so nho hon 5')

elseif d==2

d=1;

disp('nhap cac so a b c thuoc x^2/a^2+y^2/b^2-z^2/c^2=-1')

disp('nen nhap cac so nho hon 5')

syms x y lamda real

f=input('nhap ham f(x,y)= ');f=sym(f);

disp(' nhap toa do I(x0,y0) va R :')

x0=input('x0= ');

y0=input('y0= ');

r=input('R= ');

%tim cuc tri trong mien D

[p q]=solve(diff(f,'x'),diff(f,'y'));

A(i,1)=subs(f,[x y],[p(i) q(i)]);

if a>subs(f,[x y],[x0+0.12 y0+0.12])

disp(['GTLN f(' num2str(A(1,2)) ',' num2str(A(1,3)) ')= ' num2str(A(1,1))])

f=input('nhap f(x,y)= ');

y1=input('nhap y1= ');

y2=input('nhap y2= ');

disp('nhap khoang [a,b]')

a=input('a= ');b=input('b= ');

disp('nhap toa do 3 dinh A,B,C vidu: toa do la A(1,2) ta nhap: 1,2')

A=input('toa do A: ','s');A=str2num(A); %chuyen tu kieu string sang kieu so

B=input('toa do B: ','s');B=str2num(B);

C=input('toa do C: ','s');C=str2num(C);

u=diff(g,'y')-diff(f,'x');

dinh=[A;B;C];

a=unique(dinh,'rows'); %sap xep cac dinh cua tam giac, theo chieu tang dan x

S=0;

if subs(y1-y2,'x',(a(2,1)-a(1,1))/2)>0 % xem y1 hay y2 nam tren

S=S+int(int(u,'y',y2,y1),'x',a(1,1),a(2,1)); %tich phan kep

title(['x^2/' num2str(a) '^2 + y^2/' num2str(b) '^2 = 1'])

u=input('u(x,y)= ');u=sym(u);

v=input('v(x,y)= ');v=sym(v);

f=eval(f); %the u v vao f

fx=diff(f,'x'); %dao ham theo x

fy=diff(f,'y'); %dao ham theo x

disp('nhap toa do M0(x0,y0)')

x0=input('x0= ');x=x0;

y0=input('y0= ');y=y0;

z0=eval(f); %the x0 y0 vao f ta dc z0

fx1=eval(fx); %the x0 y0 vao f'x

fy1=eval(fy); %the x0 y0 vao f'y

disp(['f`x(' num2str(x) ',' num2str(y) ')= ' num2str(fx1)])

disp(['f`y(' num2str(x) ',' num2str(y) ')= ' num2str(fy1)])

syms x y real

f=input('nhap ham f(x,y)= ');

[a b]=solve([char(diff(f,'x')) '+0*x=0'],[char(diff(f,'y')) '+0*y=0'],'x','y'); % giai dao ham cap 1

[a b]=voso(a,b); % loai vo so nghiem

if a>subs(f,[x y],[x0+0.12 y0+0.12])

disp(['GTLN f(' num2str(c(1,2)) ',' num2str(c(1,3)) ')= ' num2str(c(1,1))])

x=[c(i,2)-d/10 c(i,2) c(i,2)+d/10];

y=[c(i,3)-d/10 c(i,3) c(i,3)+d/10];

x=[c(i,2)-d/10 c(i,2) c(i,2)+d/10];

y=[c(i,3)-d/10 c(i,3) c(i,3)+d/10];

if double(subs((x1-x2),'y',(a+b)/2)) > 0 % neu x1 nam ben phai x2

I=int(int(f,'x',x2,x1),'y',a,b);

I=double(I);

disp(['tich phan can tinh I= ' num2str(I)])

ve(x1,x2,a,b)

else % neu x2 nam ben phai x1

I=int(int(f,'x',x1,x2),'y',a,b);

disp(['I= ' num2str(I)])

disp('ta dat: ')

disp('nhap toa do 3 dinh A,B,C vidu: toa do la A(1,2) ta nhap: 1,2')

A=input('toa do A: ','s');A=str2num(A); %chuyen tu kieu string sang kieu so

B=input('toa do B: ','s');B=str2num(B);

C=input('toa do C: ','s');C=str2num(C);

u=diff(g,'x')-diff(f,'y');

u=-u; % theo chieu kim dong ho

dinh=[A;B;C];

a=unique(dinh,'rows'); %sap xep cac dinh cua tam giac, theo chieu tang dan x

if subs(y1-y2,'x',(a(2,1)-a(1,1))/2)>0 % xem y1 hay y2 nam tren

S=S+int(int(u,'y',y2,y1),'x',a(1,1),a(2,1)); %tich phan kep

text(a(1,1),a(1,2),['(' num2str(a(1,1)) ',' num2str(a(1,2)) ')'])

text(a(2,1),a(2,2),['(' num2str(a(2,1)) ',' num2str(a(2,2)) ')'])

text(a(3,1),a(3,2),['(' num2str(a(3,1)) ',' num2str(a(3,2)) ')'])

disp('nhap toa do M0(x0,y0,y0) thuoc mat cau x^2+y^2+z^2=4')

x0=input('x0= ');

y0=input('y0= ');

z0=input('z0= ');

if abs(x0^2+y0^2+z0^2-4)>0.00001 %kiem tra M0

disp('nhap sai M0')

n=[diff(f,'x') diff(f,'y') diff(f,'z')];

n=n/sqrt(diff(f,'x')^2+diff(f,'y')^2+diff(f,'z')^2);

%code ve mat bac 2

disp('nhap lan luoc a b c d e f g cua mat bac 2theo cong thuc sau:')

disp('a*x^2 + b*y^2/b^2 + c*z^2 + d*xy + e*xz + f*yz + g*x + h*y + i*z = j')a=input('a= ');

surf(x,y,z1,'FaceColor','r','EdgeColor','none');

mesh(x,y,z1,'EdgeColor','r','FaceAlpha',0.1);

%%%%%%%%%%%% Phan mat y=0 %%%%%%%%%%%%%%%%%%%

surf(x,y,z,'FaceColor','r','EdgeColor','none','FaceAlpha',0.5);

%%%%%%%%%%%% Phan mat x= y^2 %%%%%%%%%%%%%%%%%

surf(x,y,z,'EdgeColor','none','FaceColor','r','FaceAlpha',0.2);

%%%%%%%%%%%% Phan mat x+y+z=3 va z=0 %%%%%%%%%%

mesh(x,y,z,'EdgeColor','r','FaceAlpha',0.3);

surf(x,y,z1,'EdgeColor','none','FaceColor','g');

%%%%%%%%%% Phan mat 3x+2y=6%%%%%%%%%%%%%

mesh(x,y,z,'EdgeColor','b','FaceAlpha',0.3);

%%%%%%%%%% Phan mat 3x+y=3%%%%%%%%%%%%%

surf(x,y,z,'EdgeColor','none','FaceColor','y');

%%%%%%%%%% Phan mat y=0 %%%%%%%%%%%%%

surfc(x,y,z,'FaceColor','b','EdgeColor','r','FaceAlpha',0.7);

%%%%%%%%%%%%%%%%% Nua cau tren %%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%% Mat paraboloid va mat z=0%%%%%%%%%%%%

function [h,yy,zz] = arrow(varargin)

% ARROW Draw a line with an arrowhead

%

% ARROW(Start,Stop) draws a line with an arrow from Start to Stop (points

% should be vectors of length 2 or 3, or matrices with 2 or 3

% columns), and returns the graphics handle of the arrow(s)

% the full normal argument list, where all but the Start and Stop

% points are optional If you need to specify a later argument (e.g.,

% Page) but want default values of earlier ones (e.g., TipAngle),

% pass an empty matrix for the earlier ones (e.g., TipAngle=[])

%

% ARROW('Property1',PropVal1,'Property2',PropVal2, ) creates arrows with the

% given properties, using default values for any unspecified or given as

% 'default' or NaN Some properties used for line and patch objects are

% used in a modified fashion, others are passed directly to LINE, PATCH,

% or SET For a detailed properties explanation, call ARROW PROPERTIES

%

% Start The starting points B

% Stop The end points /|\ ^

% Length Length of the arrowhead in pixels /|||\ |

% BaseAngle Base angle in degrees (ADE) //|||\\ L|

% TipAngle Tip angle in degrees (ABC) ///|||\\\ e|

% Width Width of the base in pixels ////|||\\\\ n|

% Page Use hardcopy proportions /////|D|\\\\\ g|

% CrossDir Vector || to arrowhead plane //// ||| \\\\ t|

% NormalDir Vector out of arrowhead plane /// ||| \\\ h|

% Ends Which end has an arrowhead //< ->|| \\ |

% ObjectHandles Vector of handles to update / base ||| \ V

% E angle||< ->C

% ARROW(H,'Prop1',PropVal1, ), where H is a |||tipangle

% vector of handles to previously-created arrows |||

% and/or line objects, will update the previously- |||

% created arrows according to the current view >|A|< width

% and any specified properties, and will convert

% two-point line objects to corresponding arrows ARROW(H) will update

% the arrows if the current view has changed Root, figure, or axes

% handles included in H are replaced by all descendant Arrow objects

%

% A property list can follow any specified normal argument list, e.g.,

% ARROW([1 2 3],[0 0 0],36,'BaseAngle',60) creates an arrow from (1,2,3) to

% the origin, with an arrowhead of length 36 pixels and 60-degree base angle

%

% The basic arguments or properties can generally be vectorized to create

% multiple arrows with the same call This is done by passing a property

% with one row per arrow, or, if all arrows are to have the same property

% value, just one row may be specified

%

% You may want to execute AXIS(AXIS) before calling ARROW so it doesn't change

% the axes on you; ARROW determines the sizes of arrow components BEFORE the

% arrow is plotted, so if ARROW changes axis limits, arrows may be malformed

%

% This version of ARROW uses features of MATLAB 6.x and is incompatible with

% earlier MATLAB versions (ARROW for MATLAB 4.2c is available separately);

% some problems with perspective plots still exist

% Copyright (c)1995-2009, Dr Erik A Johnson <JohnsonE@usc.edu>, 5/20/2009

% http://www.usc.edu/civil_eng/johnsone/

% Revision history:

% 5/20/09 EAJ Fix view direction in (3D) demo

% 6/26/08 EAJ Replace eval('trycmd','catchcmd') with try, trycmd; catch,

% catchcmd; end; break's MATLAB 5 compatibility

% 8/26/03 EAJ Eliminate OpenGL attempted fix since it didn't fix anyway

% 11/15/02 EAJ Accomodate how MATLAB 6.5 handles NaN and logicals

% 7/28/02 EAJ Tried (but failed) work-around for MATLAB 6.x / OpenGL bug

% if zero 'Width' or not double-ended

% 11/10/99 EAJ Add logical() to eliminate zero index problem in MATLAB 5.3

% 11/10/99 EAJ Corrected warning if axis limits changed on multiple axes

% 11/10/99 EAJ Update e-mail address

% 2/10/99 EAJ Some documentation updating

% 2/24/98 EAJ Fixed bug if Start~=Stop but both colinear with viewpoint

% 8/14/97 EAJ Added workaround for MATLAB 5.1 scalar logical transpose bug

% 7/21/97 EAJ Fixed a few misc bugs

% 7/14/97 EAJ Make arrow([],'Prop', ) do nothing (no old handles)

% 6/23/97 EAJ MATLAB 5 compatible version, release

% 5/27/97 EAJ Added Line Arrows back in Corrected a few bugs

% 5/26/97 EAJ Changed missing Start/Stop to mouse-selected arrows

% 5/19/97 EAJ MATLAB 5 compatible version, beta

% 4/13/97 EAJ MATLAB 5 compatible version, alpha

% 1/31/97 EAJ Fixed bug with multiple arrows and unspecified Z coords

% 12/05/96 EAJ Fixed one more bug with log plots and NormalDir specified

% 10/24/96 EAJ Fixed bug with log plots and NormalDir specified

% 11/13/95 EAJ Corrected handling for 'reverse' axis directions

% 10/06/95 EAJ Corrected occasional conflict with SUBPLOT

% 4/24/95 EAJ A major rewrite

% Fall 94 EAJ Original code

% Things to be done:

% - in the arrow_clicks section, prompt by printing to the screen so that

% the user knows what's going on; also make sure the figure is brought

% to the front

% - segment parsing, computing, and plotting into separate subfunctions

% - change computing from Xform to Camera paradigms

% + this will help especially with 3-D perspective plots

% + if the WarpToFill section works right, remove warning code

% + when perpsective works properly, remove perspective warning code

% - add cell property values and struct property name/values (like get/set)

% - get rid of NaN as the "default" data label

% + perhaps change userdata to a struct and don't include (or leave

% empty) the values specified as default; or use a cell containing

% an empty matrix for a default value

% - add functionality of GET to retrieve current values of ARROW properties

% Many thanks to Keith Rogers <kerog@ai.mit.com> for his many excellent

% suggestions and beta testing Check out his shareware package MATDRAW

% (at ftp://ftp.mathworks.com/pub/contrib/v5/graphics/matdraw/) he has

% permission to distribute ARROW with MATDRAW

% Permission is granted to distribute ARROW with the toolboxes for the book

% "Solving Solid Mechanics Problems with MATLAB 5", by F Golnaraghi et al

% (Prentice Hall, 1999)

% Permission is granted to Dr Josef Bigun to distribute ARROW with his

% software to reproduce the figures in his image analysis text

% global variable initialization

global ARROW_PERSP_WARN ARROW_STRETCH_WARN ARROW_AXLIMITS

if isempty(ARROW_PERSP_WARN ), ARROW_PERSP_WARN =1; end;

if isempty(ARROW_STRETCH_WARN), ARROW_STRETCH_WARN=1; end;

if strncmp(arg1,'prop',4), arrow_props;

elseif strncmp(arg1,'demo',4)

if (nargout>3), error([upper(mfilename) ' produces at most 3 output arguments.']); end;

% find first property number

error([upper(mfilename) ' requires that the property '''

varargin{nargin} ''' be paired with a property value.']);

end;

end;

% default output

defstart = [NaN NaN NaN];

defstop = [NaN NaN NaN];

% parse property pairs

if strncmp(prop,'start' ,5), start = val;

elseif strncmp(prop,'stop' ,4), stop = val;

elseif strncmp(prop,'len' ,3), len = val(:);

elseif strncmp(prop,'base' ,4), baseangle = val(:);

elseif strncmp(prop,'tip' ,3), tipangle = val(:);

elseif strncmp(prop,'wid' ,3), wid = val(:);

elseif strncmp(prop,'page' ,4), page = val;

elseif strncmp(prop,'cross' ,5), crossdir = val;

elseif strncmp(prop,'norm' ,4), if (isstr(val)), crossdir=val; else, crossdir=val*sqrt(-1); end;

elseif strncmp(prop,'end' ,3), ends = val;

elseif strncmp(prop,'object',6), oldh = val(:);

elseif strncmp(prop,'handle',6), oldh = val(:);