not enough input argument

Hi I have a problem with my function on matlab and it's driving me crazy I am very new to matlab and I was wondering what went wrong in my command because I keep getting "not enough input argument" and this appears in my command window:

>> Tut2Q2 Not enough input arguments.

Error in Tut2Q2 (line 3) dydx = [y(2); -0.54*y(2)-(0.0729+pi)*y(1)];

My script file is:

function dydx = Tut2Q2(x,y)

dydx = [y(2); -0.54*y(2)-(0.0729+pi)*y(1)];

end

Help please! :-(

[Torsten]

Please supply the complete code you are using.

Best wishes

Torsten.

[Stephen23]

@Tze Ting Ong: how are you calling the function Tut2Q2 ?

Answer 1

[C.J. Harris]

Your code, which I've included below takes two inputs, x and y, however you don't use the first input 'x' anywhere in your code, while input y is expected to be of size 2.

function dydx = Tut2Q2(x,y)
dydx = [y(2); -0.54*y(2)-(0.0729+pi)*y(1)];
end

Therefore, unless you are calling the function with y having a size of 2, it will give that error. You could change your code to use both x and y:

function dydx = Tut2Q2(x,y)
dydx = [y; -0.54*y-(0.0729+pi)*x];
end

And then call it with two inputs:

out = Tut2Q2(1,2);

With your current definition, you'd have to call it as follows to achieve the same thing:

out = Tut2Q2([],[1 2]);