- #1

- 16

- 0

**1. The problem**

Use Differentials to approximate (24.5)^(1/2) + (9.5)^(1/2). Compare your answer to your calculator's answer.

## Homework Equations

I used z = (x)^(1/2) + (y)^(1/2)

## The Attempt at a Solution

What I used:

let z = (x)^(1/2) + (y)^(1/2)

x = 25

y = 10

dx = 0.5

dy = 0.5

Using http://www.maths.soton.ac.uk/~jav/soton/ma155/lectures2/img203.gif [Broken].[/URL]

I plugged in 1/(2(x)^(1/2)) for the partial derivative w/respect to x, and 1/(2(y)^(1/2)) for the partial derivative w/respect to y. When I plug into the formula, I get 0.1290 not 8.0139 like in the calculator. What am I doing wrong?

Last edited by a moderator: