plotting functions in matlab

Hello, can you help with this question, please?

I want to plot a function of y(theta) = sin(theta) , but matlab gives me error i don't know why.

I have tried this so far,

function [y] = myfunction(/theta)

y = sin(/theta)

end

Answer 1

[Stephen23]

function [y] = myfunction(theta) % "/" is not valid in a variable name
y = sin(theta);
end

[payam abubakr]

Thank you! it worked well

but why it gives me errorr when I multiply it by cos(2 theta)?

y = sin(theta) * cos(2 theta);

appreciate your help!

[payam abubakr]

also, it does not allow me to plot it even with this code

y = sin(theta)*cos(2*theta)

[Stephen23]

Like most programming languages, MATLAB does not have implicit multiplication of two things written next to each other: if two things are multiplied together, you need to write some multiplication operator between them.

This means your code is invalid because it is missing a multiplication operator:

cos(2 theta)?
%    ^ missing!

Try this:

cos(2*theta)

"it does not allow me to plot it even with this code"

You need to learn about array and matrix operations:

https://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html

y = sin(theta).*cos(2*theta);
%             ^^ element-wise times

[payam abubakr]

thank you! it helped me a lot.