## Integration with respect to a function of x

You might think: what the hell are you talking about? I’m talking about this: Looks crazy, right? After this lesson it’s gonna look cool, trust me! Let’s calculate the integral of x with respect to x². One day I thought: “what is the integral of a function of x with respect to x²? That’s impossible I guess.” A couple of months later, that is less than a week ago, I realised: “substitution!”. If we know how to integrate with respect to x, u, t or whatever letter it is, then… Read more Integration with respect to a function of x →