Is this step of this inequation is correct,I got it from a book and I guess its wrong or may be I am missing something
How come the sign changed? To me it doesnt make any sence.
The essence of mathematics lies in its freedom - Georg Cantor
Looks like a typo.
In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
It's wrong. The sign should've stayed the same...
Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment