This is a problem from a Calc 1 text book, I just can't figure out where they get dx from. The question is:(adsbygoogle = window.adsbygoogle || []).push({});

Use differentials to approximate the value of the expresesion.

[tex]\sqrt{99.4}[/tex]

the answer in the solution manual says:

Let [tex]f(x)=\sqrt{x}, x=100, dx=-.6[/tex]

then it solves the problem. But what I don't understand is where the heck is this dx quantity derived from?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Simple Differential Problem

**Physics Forums | Science Articles, Homework Help, Discussion**