How to implement integration with function of function.

Hi, can someone help me understand how to implement the integral in the picture?

The integrand function must be solved as a function of y, then the integrated function (CL) must be set equal to zero to find the alpha value in CL = 0.

[darova]

What is this? Do you have it?

[Luca]

This is a manner to say "derivative of alpha", I didn't.

after calculating the integral, I have to equal zero the CL that I obtained as a function of alpha in order to obtain the alpha value that cancels the CL.

[Luca]

I didn't, but... I have a matrix (106,2) with (alpha, CL).

[darova]

What is the connection between and y?

[Luca]

Forgive me, let's change: maybe this way I will solve better and sooner. So, we have CL (alpha) as fitting curve (coeff of polinomio) and alpha = a * y + b (a straight line).

How do I get CL (alpha (y))?

(How to trasform a fitting curve with coeff in a x function?)