How to correct the invalid expression error when i have the correct delimiters and multiplication operator?

I am trying to run this code, but i am getting the invalid expression error for line 6. All parathensis are correct:

xz(t)=e^(j*pi*m(t));
xp(t)=pi*m(t);
xI(t)=cos(pi*m(t));
xQ(t)=sin(pi*m(t));
Ts=50;
t=(0:Ts:3);
m(t)=((t>=0)f(t<1)).*(-1+2*t)+((t>=1)f(t<2)).*(2-t);

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Error in connector.internal.fevalMatlab

Error in connector.internal.fevalJSON

plot(t,pi*m(t));q0xp(t);
plot(t,cos(pi*m(t)));qoxz(t);
plot(t,sin(pi*m(t)));qoxQ(t);

[Voss]

What does this mean to you?

(t>0)f(t<1)

[Samuel Seckler]

updated code above, same issue. do you know how to fix this?

Answer 1

[Benjamin Kraus]

This is an invalid MATLAB expression:

(t>=0)f(t<1)

Specifically, this is invalid:

(t>=0)f

It is unclear what you intend for MATLAB to do? Should MATLAB multiply a logical vector with the value of f? What is the value of f? If you want MATLAB to do an element-by-element multiplication of the value of (t>=0) with the value of f then you need this:

(t>=0).*f

And this may be invalid, depending on the value of f and t.

f(t<1)

In this case (t<1) will be a logical vector and f can either be a function or index. If f is a function, then you are calling that function with a logical vector. If f is a variable, then you will get an invalid index for any value that is less than 1, becase 0 is not a valid index for a MATLAB vector (which is 1-based).