Okay so I know how to draw my functions

but as soon as we get into a function such as: x^2 +2x , or something like that. I get confused. My professor explained that, using the first and second derivatives of functions such as these, they can help us plot. I'm putting this under arc lengths, because this is where im having this problem. So if someong can help me with drawing more complex similar to this example, then that would be great!