hi. I want to draw the 3D PLOT of this but i can only draw 2-D. kindly help. I am new.

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rana zain 2020-8-28

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https://ww2.mathworks.cn/matlabcentral/answers/585878-hi-i-want-to-draw-the-3d-plot-of-this-but-i-can-only-draw-2-d-kindly-help-i-am-new

关闭： MATLAB Answer Bot 2021-8-20

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x = (0:(1/60):1);  % intial data as given by problem
m = length(x);
t = zeros(1,m);
t = (0:(1/60):0.5);
t(1, 32:61) = 0;
y = 40*sin(pi*x); % function vector
theta = [1; 0.2;0.8]; %initial theta
aplha = 0.1;
lambda = 2;
X = ones(m,3);
X(:,2) = x;
X(:,3) = t;
h_theta = X*theta;   
h_theta = h_theta';
% error 
J = 0;
for i = 1:m
    J = J + (h_theta(i)-y(i))^2;
end
J = J/(2*m) ;  % error using initial theta
Reg = lambda/(2*m) * sum(theta(2:3,1));
J = J + Reg
v = pinv(X'*X)*X'*y' % calculated perms
x1 = (0:0.25:1);
t1 = (0:0.1:0.4);
for i = 1:length(x1)
    pol(i) = v(1) + v(2)*x1(i) + v(3)*t1(i);
    
      
end
pol
plot3(x1,t1,pol, 'r-')

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Walter Roberson 2020-8-30

No, no one can answer the query, not unless they happen to be taking (or giving) the same clasd this is homework for, and so can supply the missing information.

We cannot plot y because there is no equation for y in what you posted. Instead there are equations for the seemingly irrelevant f and g.

rana zain 2020-8-30