testing header
Math Goodies is a free math help portal for students, teachers, and parents.
Free Math
Newsletter
 
 
Interactive Math Goodies Software

Buy Math Goodies Software
testing left nav
Math Forums @ Math Goodies
Math Forums @ Math Goodies
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 Homework Help Forums
 Pre-Calculus and Calculus
 Vector derivative proof ... with a vector function
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

Unununium111
New Member

USA
2 Posts

Posted - 01/20/2011 :  23:36:45  Show Profile  Reply with Quote
Hey there, so it has been a while since I have taken Calc, and now I find myself in Calc 3 contemplating my career choices. Needless to say, I need some help proving a simple derivative of a vector-valued function, as I have never dealt with these. Of course I never have time to meet with the teacher when I work all day, so here I am. SO the problem states if |r(t)| > 0 , then show that:
(d/dt)|r(t)| = {(1/|r(t)|)*r(t)} * {(d/dt)r(t)}

What happens as |r(t)|=0 with {(d/dt)r(t)}?

I have never seen a vector function until the other day, and I'm always uncomfortable with the 'prove this' type of general equations.

Thanks in advance for the help!
Go to Top of Page

royhaas
Moderator

USA
3059 Posts

Posted - 01/21/2011 :  12:51:54  Show Profile  Reply with Quote
I believe your second "*" is actually a dot product. Write r(t)=x(t)i+y(t)j+z(t)k and use that.
Go to Top of Page

maser22
New Member

USA
2 Posts

Posted - 04/05/2011 :  11:36:55  Show Profile  Reply with Quote
Hi,

I wanted to let you know about a superb mathematician who works as a tutor for a homework help website.

If you want to consult with her on any math issues, click on the link and submit a Solution Request. Your request will go to her directly if you enter "rlehman" in the Specialist's username field during your submission. You won't be sorry, as she is the real deal.

Please post back to me here and let me know what you think of her.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Math Forums @ Math Goodies © 2000-2004 Snitz Communications Go To Top Of Page
This page was generated in 0.1 seconds. Snitz Forums 2000
testing footer
About Us | Contact Us | Advertise with Us | Facebook | Blog | Recommend This Page




Copyright © 1998-2014 Mrs. Glosser's Math Goodies. All Rights Reserved.

A Hotchalk/Glam Partner Site - Last Modified 21 May 2014