What values of m as a function of q satisfy this trigonometric equation?

In summary, the conversation discusses a trigonometric equation and the search for values of m as a function of q that satisfy the equation. The obvious solution is q=2n and m=2, but there are more solutions that cannot be found using trigonometric identities. One possible solution is m=qπ/arcsin(1/2sin(qπ/2)), which results in q/m being an integer for q=2n. However, the speaker is looking for a simpler expression involving q, m, π, and possibly n that does not involve trigonometric functions.
  • #1
LmdL
73
1
I have a trigonometric equation
[tex]2\sin \left ( \frac{q\pi }{m} \right )-\sin \left ( \frac{q\pi }{2} \right )=0[/tex]
and want to know what values m as a function of q could take to satisfy the equation. Both terms zero is the obvious solution: q=2n; m=2; n is an integer. But there are more solutions. I tried to use different kinds of trigonometric identities, with no luck.
The best I could get is
[tex]m=\frac{q\pi}{\arcsin \left ( \frac{1}{2}\sin \left ( \frac{q\pi }{2} \right ) \right )}[/tex]
which for q=2n gives q/m is an integer.
Is there a more elegant general solution?

Thanks!
 
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  • #2
Are q and m integers?
 
  • #3
In general, for my purpose, both are continuous.
 
  • #4
You found an expression of m as function of q. What else do you need?
You can add +2 pi * k at a suitable place (where you take the arcsine) to get the other solutions for m.
 
  • #5
I'm in doubt if there is a simpler expression involving q,m,π and probably n (integer). Without trigonometric functions.
 
  • #6
That would surprise me.
 

1. What is a simple trigonometric equation?

A simple trigonometric equation is an equation that involves trigonometric functions (such as sine, cosine, and tangent) and one or more variables. These equations are used to solve for unknown angles or side lengths in a right triangle.

2. How do you solve a simple trigonometric equation?

To solve a simple trigonometric equation, you typically use algebraic techniques to isolate the variable and then use trigonometric identities and properties to simplify the equation. Once the equation is simplified, you can use inverse trigonometric functions to find the value of the variable.

3. Can you give an example of a simple trigonometric equation?

One example of a simple trigonometric equation is sin x = 0.5. This equation can be solved by taking the inverse sine of both sides, giving us x = sin-1(0.5) = 30o. This means that x is equal to 30 degrees.

4. Are there any common mistakes when solving simple trigonometric equations?

Yes, some common mistakes when solving simple trigonometric equations include forgetting to use parentheses when using inverse trigonometric functions, not simplifying the equation enough before using inverse functions, and forgetting to check for extraneous solutions.

5. How are simple trigonometric equations used in real life?

Simple trigonometric equations are used in various fields, such as engineering, physics, and astronomy. They can be used to calculate distances, heights, and angles in real-life situations, such as measuring the height of a building or determining the trajectory of a projectile.

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