# W3L2 - Help with understanding second derivative example

Dear All,

I am having issues understanding the video and the interactive tool, in both cases I cannot understand how the numbers are being calculated.

The instructor says let’s imagine the following is 750t^2

How is this calculated? Also in the tool, it says 5t^2, where and how this number is coming from? I think I am missing something fundamental here.

Thank you,
David

From what I understand the 750t2 is an approximation here, he is saying lets imagine this function is approximated by that.

The second one should be a different graph from the first one.

Hello there, thanks for the reply.

I noticed that he said let’s imagine (or an expression similar to this one) but I don’t get it and I cannot fully understand like this. I know the point is not this but how it affects the first and second derivatives but still I would like to understand.

Same goes for the second example, I know it’s different but still I don’t get it how the 5t^2 or right after, 20t-20 is coming to the picture.

I haven’t done this course but I believe that he explains how to calculate derivatives, but if he doesn’t then you need to find a source to understand how you calculate derivatives and integrals…for example the derivative of 5t^2 is 20t!