invalid expression error.

B = 0.02;
a = 0.1;
f = 0.53;

phi = 3*pi/4;

t = -5:0.05:10;

x = B^a*exp (-a*t) .*sin(...2*pi*f*t+phi);

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

xu = x.*(t>O) ;

u = (t>0);

plot(t,x,t,u,t,xu)
ylabel('x (t)')
xlabel('t (s)')
text (O, 1.2, 'Tu(t)')
text (-4,-1.1,'x (t)')
axis ([t( 1)t(end)-1.5 1.5])

Answer 1

[Torsten]

B = 0.02;
a = 0.1;
f = 0.53;

phi = 3*pi/4;

t = -5:0.05:10;

x = B^a*exp (-a*t) .*sin(...
    2*pi*f*t+phi);

xu = x.*(t>0) ;

u = (t>0);

plot(t,x,t,u,t,xu)
ylabel('x (t)')
xlabel('t (s)')
text (0, 1.2, 'Tu(t)')
text (-4,-1.1,'x (t)')
axis ([t(1) t(end) -1.5 1.5])

[John]

Thank you!