Integrating this function and trying to solve for a variable displays errors!

Here is the code with the error:

syms initial theta

ints = int(1/sqrt(cos(initial)-cos(theta)),initial,pi/2);

func = L/sqrt((E*I)/(2*F)) - ints;

S = fsolve(func,0);

S

Error using lsqfcnchk (line 108)

If FUN is a MATLAB object, it must have an feval method.

Error in fsolve (line 235)

funfcn = lsqfcnchk(FUN,'fsolve',length(varargin),funValCheck,gradflag);

Error in GuessesICs (line 65)

S = fsolve(func,0);

I am trying to solve for initial in this function. the fuction is in respect to theta (dθ) so that should not be a problem?

Anythign appreciated

Thank you

Answer 1

[Torsten]

L = 1;E = 1;I = 1;F=1;
func = @(initial) L/sqrt((E*I)/(2*F)) - integral(@(theta)1./sqrt(cos(initial)-cos(theta)),initial,pi/2);
S = fsolve(func,0.5)

Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the value of the function tolerance, and
the problem appears regular as measured by the gradient.

S = 1.1094

func(S)

ans = -8.5387e-12

[adam puchalski]

bless your soul thank you very much!