My Math Forum  

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

Algebra Pre-Algebra and Basic Algebra Math Forum


Reply
 
LinkBack Thread Tools Display Modes
February 8th, 2013, 07:25 PM   #1
Newbie
 
Joined: Feb 2013

Posts: 5
Thanks: 0

How can I find the angle X

[a*cos(b-X)]^2 = c*cos(X) where a, b, c are constant
Yasir is offline  
 
February 8th, 2013, 10:19 PM   #2
Senior Member
 
Joined: Dec 2012

Posts: 148
Thanks: 0

Re: How can I find the angle X

I am not sure about this problem... Could you check if you posted it right?!
tahir.iman is offline  
February 9th, 2013, 01:25 AM   #3
Newbie
 
Joined: Feb 2013

Posts: 5
Thanks: 0

Re: How can I find the angle X

HI

Yes it is OK. There is one unknown and one equation and I am stuck in solving the angle X.
Yasir is offline  
February 9th, 2013, 01:46 AM   #4
Newbie
 
Joined: Feb 2013

Posts: 5
Thanks: 0

Re: How can I find the angle X

Or alternatively I want to find the solution of equation given below

[a*cos(x)]^2 + b*sin(x)*cos(x) + c = cos(x) where a, b and c are constant

Thanks.
Yasir is offline  
February 9th, 2013, 10:22 PM   #5
Senior Member
 
Joined: Dec 2012

Posts: 148
Thanks: 0

Re: How can I find the angle X


Put random numbers for a, b, c (radians), try to solve and then generalize for a, b, c.
tahir.iman is offline  
February 9th, 2013, 10:35 PM   #6
Math Team
 
mathbalarka's Avatar
 
Joined: Mar 2012
From: India, West Bengal

Posts: 3,871
Thanks: 86

Math Focus: Number Theory
Re: How can I find the angle X

Quote:
Originally Posted by Yasir
[a*cos(b-X)]^2 = c*cos(X) where a, b, c are constant
Hint : Expand cos(b-x) and try writing the whole equation in terms of cos(x). It will result a quartic equation. Solving it and handling the periods would be sufficient for finding 'x'.

Quote:
Originally Posted by tahir.iman
Put random numbers for a, b, c (radians), try to solve and then generalize for a, b, c.
Wha? Why would one do that??
mathbalarka is offline  
February 9th, 2013, 11:50 PM   #7
Newbie
 
Joined: Feb 2013

Posts: 5
Thanks: 0

Re: How can I find the angle X

Thanks a lot for your help. I am trying to solve this its not as simple as it looks like e.g. i am not able to find quadratic equation with only cos(x) term.
Yasir is offline  
February 10th, 2013, 01:10 AM   #8
Math Team
 
mathbalarka's Avatar
 
Joined: Mar 2012
From: India, West Bengal

Posts: 3,871
Thanks: 86

Math Focus: Number Theory
Re: How can I find the angle X

Quote:
Originally Posted by Yasir
i am not able to find quadratic equation
I didn't said quadratic, did I? I said 'quartic'. A polynomial of degree 4.
mathbalarka is offline  
February 10th, 2013, 03:07 AM   #9
Newbie
 
Joined: Feb 2013

Posts: 5
Thanks: 0

Re: How can I find the angle X

Thanks for the clarification. I will try again to write whole equation in terms of cos(x). Previously I was ended up with an equation having one extra sin(x) term. I will try again to get rid of sin(x).
Thanks.
Yasir is offline  
February 10th, 2013, 03:16 AM   #10
Math Team
 
mathbalarka's Avatar
 
Joined: Mar 2012
From: India, West Bengal

Posts: 3,871
Thanks: 86

Math Focus: Number Theory
Re: How can I find the angle X

Try the Pythagoras theorem for writing out sin(x) in terms of cos(x), the whole calculation can get a bit messy . . .
mathbalarka is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
angle, find



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Find angle masterofmath Algebra 2 August 23rd, 2013 02:42 AM
Find Angle C Albert.Teng Algebra 4 February 20th, 2013 05:04 AM
how to find angle mariasp Complex Analysis 7 October 22nd, 2012 05:40 AM
FIND : ANGLE : APB zgonda Algebra 9 August 22nd, 2010 05:48 PM
Find the angle naserellid Algebra 6 August 15th, 2010 03:54 PM





Copyright © 2019 My Math Forum. All rights reserved.