How do I solve for the upper bound of a definite integral when I know what the integral is equal to?

Hers is what I am trying to solve:

The integral dx/(a1*sin(wx)+a2*sin(3wx) from xo to xt = C.

I know the values of everything except xt and I need to figure out how to get matlab to solve for it numerically.

[Walter Roberson]

Do we know that there is no singularity over xo to xt ?

Answer 1

[Torsten]

a1=...;
a2=...;
w=...;
xo=...;
value_integral=...;
sol = fzero(@(C)((integral(@(x)1./(a1*sin(w*x)+a2*sin(3*w*x)))-value_integral,xo,C)),1);

where value_integral is the known value of the integral.

Best wishes

Torsten.

[RPatel]

Hello Torsten,

there seems to be an error in the answer you've suggested.. Could you please rectify the same?

Cheers!

[Torsten]

Please show the code you are using and the complete error message you get.

Best wishes

Torsten.

[TUAN NGUYEN]

Hello Torsten, does your code work on MATLAB 2018b version? there was error when I try to test the code.

[Torsten]

I modified the last line of the pseudocode. Does it work now ?