Solving Trigonometric Equations?

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Homework Help Overview

The discussion revolves around solving trigonometric equations, specifically focusing on the equations sin²(x) = cos²(x) and sin(pi(x) + pi/3) = 1 within specified intervals.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the relationship between sine and cosine functions, questioning the derivation of specific values such as pi/6 and discussing the implications of sin²(x) = 1/2. There are attempts to derive solutions and clarify steps, with some participants expressing confusion about their progress.

Discussion Status

Some participants have provided hints and partial solutions, while others are still grappling with the concepts. There is a mix of attempted solutions and requests for further clarification, indicating an ongoing exploration of the problems without a clear consensus on the final answers.

Contextual Notes

Participants are working within the constraints of specific intervals for their equations, and there is mention of confusion regarding the application of trigonometric identities and the interpretation of results.

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Homework Statement


Solve sin^2(x) = cos^2(x) over the interval [0,2pi]

The Attempt at a Solution


sin^2(x) = cos^2(x)
sin^2(x) = 1-sin^2(x)
2sin^2(x) = 1
sin^2(x) = 1/2 = pi/6
sin(x) = sq root 1/2 = sq root pi/6

Unfortunately I am completely lost at this point and am not sure if I did that part correctly. If I did where would I go from here? Any help would be greatly appreciated, including any books where I could find some examples of whatever (or what) this is. Regardless, thank you for your time.
 
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Where did pi/6 come from in your fourth equation?
 
Sin(1/2) = pi/6
After I got lost I started adding things to see if I could make my own rules naturally. It has not seemed to work yet though.

Sorry figured out next few steps
sin = sq rt 1/2 = 1 sq rt 2 = sq rt 2/2 = pi/4

Thank you for helping me :).
 
Last edited:
You got sin²(x) = ½. Now you have to figure out which x's in [0,2pi] satisfy this equation. One solution is pi/4. There are three more solutions.

Hint: Draw a picture.
 
pi/4, 3pi/4, 5pi/4, 7pi/4

I appreciate the help.
 
I am sorry to be a nuisance but I cannot seem to get this.
Homework Statement
sin(pi(x) + pi/3) = 1
over interval [-1/3,2/3]

Attemps
sin(pi(x))cos(pi/3) + sin(pi/3)cos(pi(x))
1. 0(1/2) + sq rt 3 /2 - 1 = 1
- sq rt 3 / 2 = 1

2. sin(2)(1/2) + sq rt 3 /2 cos(2)

3. Throw Things -> Cry
 
I nearly resorted to step 3 as well :cry: until I had a revelation.

if sin(x)=1
then x=pi/2,5pi/2,-3pi/2 etc. = pi/2+2pi(n) , n being any integer

Therefore, sin(pi(x)+pi/3)=1

pi(x)+pi/3=pi/2+2pi(n)

I'm sure you can take it from here :smile:
 

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