Guys I have a doubt
How this definition $\integral_a^b A(x(t),y(t)) x'(t) + B(x(t),y(t))y'(t) dt $ is linked to concept of $ F* cos(\theta) * ds$
The only thing that I can't see is the $cos(\theta)$ in the first formula, where is this concept? How the first formula take the tangential component from curve?
It's thanks to derivation? If yes, why ?