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Please check My solution

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Yousif Hamzah
Yousif Hamzah 2019-9-8
评论： Walter Roberson 2019-9-9
Hi,
this is my first time I am using mathlab please help me by checking my solution if it is okay or not? also please I don't know how to rum the math lab after to see the 3 D OF THE SURGACE after finish the solution.
Q/ Run gardeint ascent , starting at (-1.6, -1.6), with Alfa= 0.2 and 63 iterations for the surface , z =f(x,y)=(e)^(-x^(2 )y^(2)) sinxy, -Pi <= x and x < Pi, -Pi <= y and y < Pi
Soluation:
>> [x,y]=meshgrid(-pi:0.1:pi,-pi:0.1:pi);
>> z=exp(-x.^2*y.^2).*sin(x*y);
>> mesh(x,y,z); axis image;
>> options= {,'interpreter','latex','fontSize',14}; % Use LATEX for labeling
>> xlabel('$x$-axis',options{:}); ylabel('$y$-axis',options{:});
>> title('ASCENT',options{:});
>> hold on
>> p=[-1.6,-1.6];
>> plot(p(1,1),p(1,2),'or','MarkerSize',10);
>> for i=1:63
x=p(1,size(p,2));
y=p(2,size(p,2));
fx=-2*x*y^2*exp(-x^2*y^2)*sin(x*y);
fy= -2*x^2*y*exp(-x^2*y^2)*sin(x*y);
p=[p p(:,size(p,2))+0.2*[fx;fy]]; % the only line that really maters
x=p(1,:); % so that you copy z componenet copy from maple
y=p(2,:);
plot(p(1,:),p(2,:),'k.-','MarkSize',7);
stem3(p(1,:),p(2,:),exp(-x.^2*y.^2).*(sinx*y),'b-+');
>> 'end'
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Yousif Hamzah
Yousif Hamzah 2019-9-9
Thank You , can you explain to me what do you mean that p(2,2) not exist on the first iteration
do yiu mean x= (pi,1);
y= (pi,2);
Walter Roberson
Walter Roberson 2019-9-9
You assign
p=[-1.6,-1.6];
That makes p a 1 x 2 scalar.
plot(p(1,1),p(1,2),'or','MarkerSize',10);
That statement is okay because p(1,1) and p(1,2) both exist.
for i=1:63
x=p(1,size(p,2));
That statement is okay because size(p,2) is 2 because p is 1 x 2, and p(1,(2)) exists.
y=p(2,size(p,2));
size(p,2) is 2 because p is 1 x 2, so you are asking to access p(2,2), but p is only 1 x 2 so that will fail.
do yiu mean x= (pi,1);
No, that would be invalid syntax.
x = (pi,1)
↑
Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.
You cannot have (expression,expression) in MATLAB, except in the context of indexing or passing parameters to functions.
It is not obvious to me why you would think that the transcendtal constant π would be useful for your calculations.

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