We usually take this for granted, but it follows from the definition of the indefinite integral. The indefinite integral is such that its derivative is the function between the curvy integral symbol and the dx. In this case the function is the constant a.
So, to prove this integral we simply have to derive the function we have to the right of the equal sign. We obviously get the function a. To prove that any indefinite integral, we simply have to derive the right side of the equation. If we get the function inside the integral, it means we got it right.
Just want to thank and congrats you beacuase this project is really noble. Thank you very much.
Diego Aguilera, Argentina
THANKS FOR ALL THE INFORMATION THAT YOU HAVE PROVIDED. IT CHANGED MY PERCEPTION TOWARD CALCULUS, AND BELIEVE ME WHEN I SAY THAT CALCULUS HAS TURNED TO BE MY CHEAPEST UNIT. THANKS ONCE AGAIN.