Need help for modelling an integral

[iruril]

I have encounter to program a derivative du/dt with an integral with respect to phi, may I ask how could I approach the problem?

How could I do aproximate for the derivtive and then for the integral?

I have all the values in each integral and for the derivatives as well, so I guess I could do an approximation, but how to appraoch it?

thanks a lot

[webJose]

Google up equation solving by numerical methods such as the Newton-Raphson method.