Schmitt Trigger calculations

Hi all,

I was reading the article in the link below:

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/schmitt.html

Can someone please explain to me how he derived to the last step? I cannot clearly understand how he proceeded from one step to the others in the equation below.

Any help would be highly appreciated.
Thanks and sorry for my poor English.

Thanks and sorry for my poor English.

Click to expand...

I will excuse your English if you excuse my spidery hand writing.
(Actually your English seems fine).

Have a look at this:


Hopefully you can follow my working.

JimB

Hi JimB. Your hand writing was neat enough for me to understand Thanks a lot for your help.