
Calculus Calculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
March 19th, 2017, 06:43 PM  #1 
Member Joined: Feb 2017 From: henderson Posts: 36 Thanks: 0  Find the tangent line approximation
Find the tangent line approximation for f(x) = 1/x near x=8 so I used the f(a) +f'(a)(xa) f = 1/x f' = 1/x^2 I end up writing y  1/8 = 1/64 (x + 8) my answer I get is 1/64  1/4, but it's wrong so I am stuck. :/ Any help? Last edited by skipjack; March 19th, 2017 at 11:12 PM. 
March 19th, 2017, 07:15 PM  #2 
Senior Member Joined: Sep 2015 From: CA Posts: 1,206 Thanks: 614 
$f(x)=\dfrac 1 x$ $f'(x) = \dfrac{1}{x^2}$ $f(8) = \dfrac 1 8$ $f'(8) = \dfrac{1}{64}$ $f(x) \approx \dfrac 1 8  \dfrac {1}{64}\left(x  8\right) = \dfrac{1}{64}x +\dfrac 1 4$ you're trying to produce a function of $x$, not a number. 

Tags 
approximation, find, line, tangent 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
How to find the following tangent line  noobinmath  PreCalculus  4  March 23rd, 2016 10:31 AM 
How to find the tangent line?  DerGiLLster  Calculus  1  October 20th, 2015 07:04 PM 
Find the equation of the tangent line to G(x) .  Shamieh  Calculus  2  October 7th, 2013 05:12 AM 
Find an equation of the Tangent Line  Shamieh  Calculus  3  September 23rd, 2013 02:16 PM 
Find eqation of tangent line  SSmokinCamaro  Calculus  2  March 1st, 2009 01:54 PM 