My Math Forum  

Go Back   My Math Forum > High School Math Forum > Trigonometry

Trigonometry Trigonometry Math Forum


Reply
 
LinkBack Thread Tools Display Modes
October 29th, 2007, 12:25 PM   #1
Newbie
 
Joined: Oct 2007

Posts: 3
Thanks: 0

Help-Finding the slope of a tangent

I'm Canadian so I'm taking "advanced functions and relations" which is a mandatory course first semester before calc. second.


I need help with a couple questions but I'll make a different thread for each one. Anyway lets get started.


I cannot understand how to come to the final answer on this question.
Find the slope of the tangent to each curve at the given point.

Remember i have not taken calc. so i will not know anything about derivatives, so don't use that in your answer.


y= square root (cant find symbol on keyboard) of 25-x^2; (3,4)

Answer = -3/4


If anyone out there can show me how to do this, it would be much appreciated.
Incinerated is offline  
 
October 29th, 2007, 12:30 PM   #2
Senior Member
 
Joined: Dec 2006

Posts: 1,111
Thanks: 0

Do try to make your post titles more descriptive and use better language. Thanks,
Moderator.
Infinity is offline  
October 29th, 2007, 12:37 PM   #3
Newbie
 
Joined: Oct 2007

Posts: 3
Thanks: 0

Quote:
Originally Posted by Infinity
Do try to make your post titles more descriptive and use better language. Thanks,
Moderator.

fine, but she really does suck...
Incinerated is offline  
October 29th, 2007, 12:40 PM   #4
Senior Member
 
Joined: Dec 2006

Posts: 1,111
Thanks: 0

Quote:
fine, but she really does suck...
That may be true, but keep in mind it's your job to learn the material whether or not there is any teacher there at all, let alone whether they can actually teach.
Infinity is offline  
October 29th, 2007, 02:54 PM   #5
Newbie
 
Joined: Oct 2007

Posts: 3
Thanks: 0

Quote:
Originally Posted by Infinity
Quote:
fine, but she really does suck...
That may be true, but keep in mind it's your job to learn the material whether or not there is any teacher there at all, let alone whether they can actually teach.
thats why I'm here, I've only been living in the city I'm currently in for a year, (gr.11 and now) i really dont have many friends and any in that class.


So this is how i'ma learn this.

If you have any FAQ's, self help, sticky's, etc.. i would be glad to read em'
Incinerated is offline  
October 29th, 2007, 04:49 PM   #6
Senior Member
 
Joined: Dec 2006

Posts: 1,111
Thanks: 0

Good choice! Learning is great fun, especially when you can manage your education by yourself. A teacher can greatly help, but letting the teacher manage everything you do doesn't always work.
Infinity is offline  
October 29th, 2007, 07:24 PM   #7
Member
 
Joined: Oct 2007
From: CA, USA

Posts: 46
Thanks: 0

Alright, you need to use derivatives. Granted, that it doesn't have to be calculus derivatives, but nonetheless, a derivative is the slope of the line tangent to a point on the graph.

There are three equations you can used called difference quotients.
Forward DQ: (f(x) - f(x-.001))/.001
Backwards DQ (f(x+.001) - f(x))/.001
Symmetrical DQ: (f(x+.001) - f(x-.001))/.002

I plugged in the equation into all three, and I got -0.75 all three times.
mahuirong is offline  
October 30th, 2007, 02:20 AM   #8
Global Moderator
 
Joined: Dec 2006

Posts: 20,973
Thanks: 2224

You would need calculus for graphs in general, but simple geometry suffices in certain cases, including the specific case you are asking about.

The curve y = √(25-x^2) is a semicircle. The slope of the radius to the point (3, 4) is 4/3. The tangent through (3, 4) is perpendicular to that radius and hence has slope -1/(4/3), i.e., -3/4.

Note: some graphs (including this semicircle) have tangents which are perpendicular to the x-axis and therefore don't have a slope.
skipjack is offline  
Reply

  My Math Forum > High School Math Forum > Trigonometry

Tags
helpfinding, slope, tangent



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
slope and tangent line texaslonghorn15 Calculus 2 June 21st, 2013 07:52 PM
Finding slope of tangent line pomazebog Calculus 5 January 27th, 2012 10:33 PM
Slope of a tangent Striker2 Trigonometry 1 March 11th, 2010 03:49 AM
Slope of tangent line. Emily14:) Calculus 12 November 8th, 2009 06:42 AM
Slope of the tangent AdamL Calculus 2 September 17th, 2007 05:25 PM





Copyright © 2019 My Math Forum. All rights reserved.