MATLAB: Why this message error ?:Array indices must be positive integers or logical values

Question

Hi,

When i write this little script:

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demo matlab

 t = (10:1:200)';
 y = sin(2*pi*50*t)

z = y(t-10)

w = y+z

plot(t(1:50),w(1:50))

sound(w,Fs);

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there is a message error: message error: Array indices must be positive integers or logical values.

Howewer,when i write this:

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demo matlab

 t = (0:0.001:100)';
 y = sin(2*pi*50*t)

plot(t(1:50),y(1:50))

sound(y,Fs);

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there is no message error.

Why?

thanks

Answer 1

It's pretty well explained by the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_fix_the_error_.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22.3F