Derivative Rationalizing

mathitup

New member
Code:
__1________       -    ___1_____
√(x+h)² - 5             √(x²-5)
________________________________
h
sorry about that, i hope this helps
I need to find out how to rationalize this

pka

Elite Member
First, simply the fraction $$\displaystyle \frac{{\sqrt {x^2 - 5} - \sqrt {\left( {x + h} \right)^2 - 5} }}{{h\left( {\sqrt {x^2 - 5} } \right)\left( {\sqrt {\left( {x + h} \right)^2 - 5} } \right)}}$$.
Then rationalize by multiplying numerator and denominator by $$\displaystyle \sqrt {x^2 - 5} + \sqrt {\left( {x + h} \right)^2 - 5}$$

You can get help with TEX by going to the Forum Help tab at the top.
If you use Windows, I urge you to look into TeXaide.

mathitup

New member
so what happened to the 1's on top in the first part of the question, how were you able to get rid of those?

Unco

Senior Member
Cross multiply.

By the way, if you ever want to get the code tags to work, type it in notepad and copy over - it looks like it should that way.

mathitup

New member
oh alright thanks alot, so i just cross the top as it was its own equation? and then its all overe h and then i multiply by the roots to rationalize?