Using the Integral-function

Hi, I have a problem using the function integral on Matlab R2018b.

The error is: Too many Input arguments.

function [t]=schwingungsdauerK6_A3(L,phi0)
g=9.81;
k=sin((phi0)./2);
koeff=4*sqrt(L./g);
fun=@(x) 1./(sqrt(1-(k.*(sin(x))).^2));
u=integral(fun,0,(2*pi));
t=koeff.*u
end

and I start it with this script.. for example

L=9.81
phi0 =30 degree
disp('Schwingungsdauer bei phi0= 30Grad');
erg=schwingungsdauerK6_A3(9.81,30);
fprintf('Schwingungsdauer beträgt %.2f sec',erg);

Can anyone tell my where my mistake is?

Answer 1

[madhan ravi]

Bitte ausprobieren:

L=9.81
phi0 =30 %degree
disp('Schwingungsdauer bei phi0= 30Grad');
erg=schwingungsdauerK6_A3(9.81,30);     %function call
fprintf('Schwingungsdauer beträgt %.2f sec\n',erg);

function [t]=schwingungsdauerK6_A3(L,phi0) %function definition
g=9.81;
k=sind((phi0)./2);
koeff=4*sqrt(L./g);
fun=@(x) 1./(sqrt(1-(k.*(sin(x))).^2));
u=integral(fun,0,(2*pi));
t=koeff.*u
end

command window:

>> COMMUNITY

L =

    9.8100


phi0 =

    30

Schwingungsdauer bei phi0= 30Grad

t =

   25.5703

Schwingungsdauer beträgt 25.57 sec
>> 

[Torsten]

k = sind(phi0/2);

[madhan ravi]

Thanks Torsten corrected it

[madhan ravi]

it doesn't work

doesn't explain anything what error message are you getting ? paste the complete error code . See edited answer I am able to get the answer without any errors.

[Matthias Radspieler]

Yes, I edited the error massage. So it seems, that it is an specific problem, maybe wrong settings?

[madhan ravi]

try clear all at the very beginning and try again if not do the below:

type

whos integral %in command window
which integral -all

[Matthias Radspieler]

>> whos integral

>> which integral -all

C:\Users\Matthias\Documents\MATLAB\integral.m

C:\Program Files\MATLAB\R2018b\toolbox\matlab\funfun\integral.m % Shadowed

>>

.. I don´t any answer from Matlab for 'whos integral'.

[madhan ravi]

C:\Program Files\MATLAB\R2018b\toolbox\matlab\funfun\integral.m  % Shadowed

As the message clearly says that you have some file with the name of integral please remove it or rename because it's shadowing the in-built function integral

[madhan ravi]

if it solved your query make sure to accept my answer!

Answer 2

[Matthias Radspieler]

Thanks for your help, but it still doesn´t work.

I don´t know, where the problem is..

Error using integral

Too many input arguments.

Error in schwingungsdauerK6_A3 (line 12)

u=integral(fun,0,(2*pi));

Error in K6_A3_global (line 18)

erg=schwingungsdauerK6_A3(9.81,30); %function call

[Star Strider]

This is the problem:

C:\Users\Matthias\Documents\MATLAB\integral.m

The solution is to rename your function to something that is meaningful to you and does not overshadow any built-in MATLAB functions.

Answer 3

[Matthias Radspieler]

Thank you so much for your help. Now it works perfectly! That was incredibly stupid of me.

[Star Strider]

Not stupid. Just human!