Simplifying/Proving a Trigonometric Question

  • Thread starter Thread starter BlackHole213
  • Start date Start date
  • Tags Tags
    Trigonometric
Click For Summary

Homework Help Overview

The discussion revolves around proving a trigonometric identity involving secant and sine functions. The original poster presents the equation secA(1+sinA) = (1+sinA+cosA)/(1-sinA+cosA) and shares relevant trigonometric identities they are familiar with.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to simplify the left side of the equation and manipulate the right side to find equivalence. They express uncertainty about their results and seek further input on their approach. Other participants suggest multiplying both sides by a specific term and using the conjugate to aid in simplification.

Discussion Status

Participants are actively engaging with the problem, offering suggestions for manipulation and expressing willingness to share their work. There is no explicit consensus on the best approach yet, but guidance has been provided to explore different methods of simplification.

Contextual Notes

The original poster notes that this is a bonus question, indicating that they may not have access to all relevant formulas or identities, which could affect their approach.

BlackHole213
Messages
33
Reaction score
0

Homework Statement



Prove:

secA(1+sinA) = (1+sinA+cosA)/(1-sinA+cosA)


Homework Equations



I have the following equations:

sin2x + cos2x = 1
1 + tan2x = sec2x
1 + cot2x = csc2x
sin(A+B) = sinAcosB + cosAsinB
sin(A-B) = sinAcosB - cosAsinB
cos(A+B) = cosAcosB - sinAsinB
cos(A-B) = cosAcosB + sinAsinB
sin(2A) = 2sinAcosA
cos(2A) = cos2 - sin2A

These formulas are all I have, but as this is a bonus question, there might be other formulas which I am unaware of.


The Attempt at a Solution



I looked at https://www.physicsforums.com/showthread.php?t=423847 to see if I could get inspiration to achieve an answer. I've tried simplifying the left side to (1+sinA)/cosA and then I attempted to see if I could get the right hand side to equal that. I've multipled the RHS by (1+sinA+cosA)/(1+sinA+cosA), (1-sinA+cosA)/(1-sinA+cosA) and I've tried multiplying the RHS by its reciprocal and the LHS by cosA/(1+sinA). In that last attempt, I achieved an answer of 1=1, but I have a feeling that is incorrect and I'll need at least one trigonometric function in the solution.

If anyone wants to see the work that I've done in each attempt, just tell me and I'll post it.

Thanks for the assistance.
 
Physics news on Phys.org
Always remember to multiply by the conjugate.

[PLAIN]http://img337.imageshack.us/img337/1976/50453339.jpg
 
Last edited by a moderator:
Thank you, both of you.
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 9 ·
Replies
9
Views
12K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
5
Views
4K
  • · Replies 11 ·
Replies
11
Views
3K