Using Differentials to approx. a radical

[mattflint50]

I am studying for the Calculus AP exam and I am not sure how to do this problem. It asks me to find the square root of 9.5 using differentials. I have no idea how to to this. My only thought is to use y=radical x. But how do I go from there?


Your help is truely appreciated!

 

[stapel]

They probably expect you to use x = 9 and delta-x = 0.5. Then plug into the formula they gave you.

Eliz.