My Math Forum  

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

Trigonometry Trigonometry Math Forum


Thanks Tree1Thanks
Reply
 
LinkBack Thread Tools Display Modes
April 3rd, 2019, 01:07 AM   #1
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

Problem involving a unit circle and two other coordinates

I have a little problem that I hope the community would be able to assist me with.

I have a unit circle and inside that unit circle I have a point (A), outside that unit circle I have another point (B). Is there a way to find the coordinates of the point that intersects the radius of the unit circle and the line AB ?

Am I making the problem clear enough ?
R4tt3xx is offline  
 
April 3rd, 2019, 01:27 AM   #2
Senior Member
 
Joined: Feb 2016
From: Australia

Posts: 1,838
Thanks: 653

Math Focus: Yet to find out.
If by intersects the radius you mean intersects the circle, then yes, you have all the information you need.
Joppy is offline  
April 3rd, 2019, 02:31 AM   #3
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

Awesome any ideas as to any online resources that I can use to figure it out ?

I am not a school student and need to figure this out for a little "Project"

Thanks...
R4tt3xx is offline  
April 3rd, 2019, 04:31 AM   #4
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

My math skills are not very good and I would really appreciate the assistance, how would I even google such a problem ?

Thanks

R4tt3xx is offline  
April 3rd, 2019, 05:31 AM   #5
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 3,018
Thanks: 1604

Quote:
Originally Posted by R4tt3xx View Post
I have a little problem that I hope the community would be able to assist me with.

I have a unit circle and inside that unit circle I have a point (A), outside that unit circle I have another point (B). Is there a way to find the coordinates of the point that intersects the radius of the unit circle and the line AB ?

Am I making the problem clear enough ?
Understand there are an infinite number of radii in a circle. Every point between point A inside the circle and the point on the unit circle where AB intersects the circle is a point on one of those many radii.
skeeter is offline  
April 3rd, 2019, 06:00 AM   #6
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

Let me rephrase what I want to do..

I have a circle and a line starting in the circle, radius 1, which ends outside the circle. I want to know what formulas I would use to determine the x and y coordinate of intersection point between circle radius 1 and the line.

For example. Point A and the center of my circle, coordinate 0,0 are both the same. Point B is 2 units away at coordinate 0,2. 0,1 is my intersection point.

Thankyou for your time..
R4tt3xx is offline  
April 3rd, 2019, 06:06 AM   #7
Global Moderator
 
greg1313's Avatar
 
Joined: Oct 2008
From: London, Ontario, Canada - The Forest City

Posts: 7,964
Thanks: 1148

Math Focus: Elementary mathematics and beyond
Quote:
Originally Posted by R4tt3xx View Post
Point A and the center of my circle, coordinate 0,0 are both the same. Point B is 2 units away at coordinate 0,2. 0,1 is my intersection point.
The radius of such a circle is concurrent to AB so there are an infinite number of intersection points.

Perhaps it's not clear to me exactly what you mean.
greg1313 is offline  
April 3rd, 2019, 06:24 AM   #8
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

Ok allow me to rephrase then...

I am only interested in the outer most edge of the circle where the radius is 1
R4tt3xx is offline  
April 3rd, 2019, 06:37 AM   #9
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 3,018
Thanks: 1604

Since A is at the origin and the unit circle is also,then the point of intersection for that segment AB and the circle would be

$(x,y) = (\cos{\theta},\sin{\theta})$ where

$\cos{\theta} = \dfrac{x_B}{\sqrt{x_B^2 + y_B^2}}$ and $\sin{\theta} = \dfrac{y_B}{\sqrt{x_B^2 + y_B^2}}$
skeeter is offline  
April 3rd, 2019, 12:18 PM   #10
Newbie
 
Joined: Apr 2019
From: South Africa

Posts: 7
Thanks: 0

What if A was at any location within the circle of radius 1 ?

Sorry for asking another question...
R4tt3xx is offline  
Reply

  My Math Forum > High School Math Forum > Trigonometry

Tags
circle, coordinates, involving, problem, unit



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Engineering Statics problem, involving a circle and a block Volle Physics 2 July 5th, 2016 12:52 PM
Unit Circle Problem doryyroryy Pre-Calculus 1 November 15th, 2014 04:18 AM
Unit circle problem! Aiyla Algebra 1 February 14th, 2012 12:48 AM
Unit circle problem brunojo Algebra 0 March 20th, 2009 04:50 PM
Unit circle problem Nate Algebra 1 December 25th, 2008 02:16 PM





Copyright © 2019 My Math Forum. All rights reserved.