Difference two square roots.
Possible method: Use the ``conjugate expression'', i.e. the expression with the middle sign reversed.
, and compute its limit at
. We have:
thus this is an undeterminate case. We multiply and divide bythe conjugate expression:
The numerator is constant and the denomainator has an infinite limit at
. Here too we have an undeterminate case; we use the same method as above.
We transformed an undeterminate case into another one: both numerator and denominator have an infinite limit at
. We use now a variant of te method exposed in subsection subsection limit polynomial and rational.