My Math Forum  

Go Back   My Math Forum > High School Math Forum > Pre-Calculus

Pre-Calculus Pre-Calculus Math Forum


Thanks Tree1Thanks
  • 1 Post By skeeter
Reply
 
LinkBack Thread Tools Display Modes
April 14th, 2015, 08:50 AM   #1
Newbie
 
Joined: Feb 2015
From: Scotland

Posts: 20
Thanks: 0

Differentiation

Hi All,

I'm a bit stuck with this and any help would be appreciated...

h(x) = sqrt(x^2-5)

Determine the coordinates of the points where the tangent to the curve h(x) has gradient -3/2

I differentiated and got x/sqrt(x^2-5). First of all, is this correct?

Second, if this x/sqrt(x^2-5) = -3/2 how do you solve it? I always have trouble with x when it's in a fraction.

I tried x= -3(sqrt(x^2-5))/2 but got stuck again with the half power on (x^2-5).
MathDino is offline  
 
April 14th, 2015, 08:55 AM   #2
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 3,034
Thanks: 1621

your derivative is correct

$\displaystyle \frac{x}{\sqrt{x^2-5}} = -\frac{3}{2} \implies x < 0$

$\displaystyle 2x = -3\sqrt{x^2-5}$

$\displaystyle 4x^2 = 9(x^2-5)$

$\displaystyle x = -3$
Thanks from MathDino
skeeter is offline  
April 14th, 2015, 08:58 AM   #3
Newbie
 
Joined: Feb 2015
From: Scotland

Posts: 20
Thanks: 0

Wow, thanks. You make it look so easy. I had times it by two but missed squaring everything.
MathDino is offline  
Reply

  My Math Forum > High School Math Forum > Pre-Calculus

Tags
differentiation



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Difference between vector differentiation and parametric differentiation Mr Davis 97 Calculus 1 March 9th, 2015 04:50 AM
differentiation Soulanoid Calculus 1 September 29th, 2014 08:56 PM
Differentiation! Ter Calculus 8 August 16th, 2012 09:12 AM
differentiation in C florian101 Calculus 1 December 22nd, 2009 06:42 AM
Differentiation MyNameIsVu Calculus 1 June 3rd, 2009 05:18 AM





Copyright © 2019 My Math Forum. All rights reserved.