# where am i going wrong? i get errors when i multiply the functions

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Emmanuel on 13 Mar 2014
Commented: Emmanuel on 13 Mar 2014
Plot the following function from t=1 to t=2, sin(2*pi*3*t)*sin(2*pi*15*t). Label both axes, and give the plot a title. so this is the code i wrote but i keep get error. i am new at using matlab. I would like to know what i am doing wrong.
t= (1:1.1,2); x= sin(2*pi*3*t) y= sin(2*pi*15*t) c= (x*y)

nl2605 on 13 Mar 2014
for t = 1:2
x(t) = sin(2*pi*3*t);
y(t) = sin(2*pi*15*t);
c(t) = x(t).* y(t);
end
This should work
Emmanuel on 13 Mar 2014
thanks. that was quite helpful the coresponding plot matches my manually generated graph.

Joseph Cheng on 13 Mar 2014
couple of things with your line.
1. for the t=1:1.1:2 are you attempting to get t=1 to 2 with increments of .1?if so it should look more like t=1:.1:2;
2. you should have a ";" after each function execution or atleast a "," to separate what you are doing. if you don't it will try to execute
t= (1:.1:2); x= sin(2*pi*3*t);y= sin(2*pi*15*t);c= (x.*y) as one single command.
3. the c = (x*y) will also give an error when it gets that far due to the matrix multiplication dimension mismatch. you'll have to use the element-by-element multiplication ".*". See element-by-element multiplication finally your line should look like
t= (1:.1:2); x= sin(2*pi*3*t);y= sin(2*pi*15*t);c= (x.*y)