Unrecognized function or variable

syms t
x(t) = piecewise (t>=0, sin(3*t), t>=2*pi, sin(3*t)^2, t>3*pi,0);
t1 =0:0.1:3*pi;
x=subs(x,t,t1);
plot(t1,x)
xlabel('Time')
ylabel('x(t)')
disp('Energy of x(t)')
Energy of x(t)
I1 = int(sin(3*t)^2);
I2 = int(sin(3*t)^4);
E = I1(2*pi)-I1(0)+I2(2*pi)-I2(3*pi)
Energy of x(t)
Unrecognized function or variable 'Energy'.
This is my code I'm not sure why it is saying unrecognized function any help would be appreciated thank you.

Answers (3)

Steven Lord
Steven Lord on 8 Feb 2021
I suspect you copied and pasted what had been typed and/or displayed in the Command Window (including the text that your disp call displayed, namely "Energy of x(t)") into a file in the Editor/Debugger and tried to run it. You'll need to delete or comment out the displayed text in the file in the Editor/Debugger..

1 Comment

ok I fixed that now I'm getting
syms t
x(t) = piecewise (t>=0, sin(3*t), t>=2*pi, sin(3*t)^2, t>3*pi,0);
t1 =0:0.1:3*pi;
x=subs(x,t,t1);
plot(t1,x)
xlabel('Time')
ylabel('x(t)')
disp('Energy of x(t)')
I1 = int(sin(3*t)^2);
I2 = int(sin(3*t)^4);
E = I1(2*pi)-I1(0)+I2(2*pi)-I2(3*pi)
Index exceeds the number of array elements (1).
Error in sym/subsref (line 902)
R_tilde = builtin('subsref',L_tilde,Idx);

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Following Steven’s answer would clear that error but you will have a following error, so change that part of your code to the following:
%Energy of x(t)
I1(t) = int(sin(3*t)^2);
I2(t) = int(sin(3*t)^4);
E = I1(2*pi)-I1(0)+I2(2*pi)-I2(3*pi)
%Energy of x(t)
p = [ 0.1987 0.2722 0.0153 0.4451 0.466 0.8462 0.2026 0.8381 0.6813 0.8318 0.7095 0.3046 0.1934 0.3028 ;
0.6038 0.1988 0.7468 0.9318 0.4186 0.5252 0.6721 0.0196 0.3795 0.5028 0.4289 0.1897 0.6822 0.5417 ];
net = newc ([0 1 ; 0 1],6);
net.IW {1,1};
net.b {1};
net = train (net,p);
%Mencari pengelompokan vektor
b = sim(net,p);
ac = vec2ind(b);
net = init(net);
net.trainParam.epochs = 500 ; %pelatihan kohonen
net = train(net,p);
Unrecognized function or variable 'newc'.
Error in JKohonen (line 5)
net = newc ([0 1 ; 0 1],6);

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on 8 Feb 2021

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