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Originally posted by abingchem at 2011-01-04 16:16:46:
Óиö·Ö¶Îº¯Êý£º
            | x + y, x>=0  and y >=0
            | x^2 + y, x>=0 and y<0
f(x,y) = | x + y^2,  x <0 and y >=0
            | x^2 + y^2, x<0 and y <0
Èç¹û²Î ...

clear
clc

fxy = @( x, y )x .* ( x >= 0 & y >= 0 ) + y .* ( x >= 0 & y >= 0 ) +...
    x .^ 2 .* ( x >= 0 & y < 0 ) + y .* ( x >= 0 & y < 0 ) + ...
    x .* ( x < 0 & y >- 0 ) + y .^ 2 .* ( x < 0 & y >- 0 ) + ...
    x .^ 2 .* ( x < 0 & y < 0 ) + y .^ 2 .* ( x < 0 & y < 0 );

%% Èç¹ûx¡¢y¶¼ÊÇÊý×éµÄ»°
x = -10 : 0.1 : 10;
y = -10 : 0.1 : 10;
z1 = fxy( x, y );

figure
plot3( x, y, z1 )

%% À©Õ¹µ½x£¬y¶¼ÊǾØÕó
[ x, y ] = meshgrid(  -10 : 0.1 : 10, -10 : 0.1 : 10 );
z2 = fxy( x, y );

figure
surf( x, y, z2 )

Originally posted by xiegangmai at 2011-01-04 18:03:53:


fxy = @( x, y )x .* ( x >= 0 & y >= 0 ) + y .* ( x >= 0 & y >= 0 ) +...
    x .^ 2 . ...

Originally posted by abingchem at 2011-01-05 11:44:09:


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Originally posted by xiegangmai at 2011-01-05 12:53:05:


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