Thread: Dealing with formulas

Hi everyone. First of all, congratulations for the forum.
I'm trying to grasp, as a complete beginner, some concepts of Math. I'm reading "Mathematics: its content methods and meaning"
I have a doubt (it won't be the last )
Mathematics: Its Content, Methods and Meaning - Aleksandr Danilovich Aleksandrov, Andréi Nikoláevich Kolmogórov, M. A. Lavrent'ev - Google Libros

I hope the link works, if it doesn't I'll copy the example.
I don't understand the step in page 67
S₂=g(t + At)² / 2 = gt²/2 + g/2 (2tAt + At²)
It's this part in bold that I don't know where it comes from.

I hope the notation is legible and my English readable.

Yay for Russian mathematics!

Originally Posted by Berengario

I don't understand the step in page 67
S₂=g(t + At)² / 2 = gt²/2 + g/2 (2tAt + At²)
It's this part in bold that I don't know where it comes from.

This is because (t + Δt)² = t² + 2tΔt + (Δt)².

Right... So I'm missing also some essential Physics...

Thank you very much!
Большое спасибо!

It's a great book... I'll try to go as far as possible.