Solving Trigonometric Equations with multiple solutions

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SUMMARY

The discussion focuses on solving the trigonometric equation 2 sin x = √3 within the interval 0 ≤ x ≤ 2π. The correct solutions identified are x = π/3, 2π/3, 4π/3, and 5π/3. It is clarified that while sin(π/3) and sin(2π/3) yield positive results, the negative results from sin(4π/3) and sin(5π/3) do not satisfy the original equation, emphasizing that √a is not equivalent to -√a. This distinction is crucial for accurately determining valid solutions.

PREREQUISITES
  • Understanding of basic trigonometric functions and their properties
  • Knowledge of solving equations involving trigonometric identities
  • Familiarity with the unit circle and angle measures in radians
  • Ability to interpret and manipulate square roots in mathematical equations
NEXT STEPS
  • Study the unit circle to reinforce understanding of sine values
  • Learn about the properties of trigonometric functions and their inverses
  • Explore solving more complex trigonometric equations with multiple solutions
  • Review the implications of positive and negative roots in equations
USEFUL FOR

Students studying trigonometry, educators teaching mathematical concepts, and anyone looking to deepen their understanding of solving trigonometric equations with multiple solutions.

Sadriam
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Homework Statement


Solve each equation for solutions on the interval 0 ≤ x ≤ 2∏.
Code:
2 sin x = √3

The Attempt at a Solution


Okay so I was able to solve this one:

  • 2 sin x = √3
  • sin x = (√3) / 2

So i got x = ∏/3 ; 2∏/3 ; 4∏/3 ; 5∏/3

I substituted the x's into the original problem, and ∏/3 and 2∏/3 give +(√3). The other two give -(√3). Are the one's that give negative results also solutions? If so, is this only true for (±√x), or is the sign always a significant factor?
 
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No, if [itex]sin(x)= -\sqrt{3}/2[/itex] then [itex]2sin(x)= -\sqrt{3}[/itex] which is NOT the original equation. Those values of x do NOT satisfy the equation and are NOT solutions. In particular, [itex]\sqrt{a}[/itex] is NOT the same as either [itex]-\sqrt{a}[/itex] or [itex]\pm\sqrt{a}[/itex].
 
Thank you for clarifying (:
 

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