Tired and not understanding Calculus. So, velocity equals dx/dt and acceleration is dv/dt But to derive the constant acceleration equations, my professor took the integral of vdt = dx, which we got from v = dx/dt. I follow all of the math that comes after that, but I don't understand why this integral produces equations for constant acceleration. Why are we taking the integral of velocity if acceleration is the derivative of velocity, and why does this only work for constant acceleration? Thanks.