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Math Help - Help with this proof. Not exactly sure where to start.

  1. #1
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    Help with this proof. Not exactly sure where to start.

    The statement is:

    "For each real number p, there exist real numbers q and r such that qsin(r/5) = p."

    We have to either prove this statement or give a counter-example.

    I've been talking with others in my class and it seems like the first thing we need to do is say:

    "Let p be a real number. Put r = (5/2)(pi)."

    And then I plugged this in for r in the equation, getting q = p.

    Is this correct? If not, what am I doing wrong? Thanks in advance for the help
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  2. #2
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    Quote Originally Posted by Lprdgecko View Post
    The statement is:

    "For each real number p, there exist real numbers q and r such that qsin(r/5) = p."

    We have to either prove this statement or give a counter-example.

    I've been talking with others in my class and it seems like the first thing we need to do is say:

    "Let p be a real number. Put r = (5/2)(pi)."

    And then I plugged this in for r in the equation, getting q = p.

    Is this correct? If not, what am I doing wrong? Thanks in advance for the help
    That is exactly what I would do.

    Additional note: I would start out by writing "Let q = p and r = (5/2)pi. Then...."
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  3. #3
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    Quote Originally Posted by undefined View Post
    That is exactly what I would do.
    So, I am a little confused on what we are trying to prove. Do we need to prove that q = p or are we proving that qsin(r/5) = p?
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  4. #4
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    Quote Originally Posted by Lprdgecko View Post
    So, I am a little confused on what we are trying to prove. Do we need to prove that q = p or are we proving that qsin(r/5) = p?
    I added an additional note to my first post, not quickly enough I guess. Let me know if it's still not clear.
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  5. #5
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    Quote Originally Posted by undefined View Post
    I added an additional note to my first post, not quickly enough I guess. Let me know if it's still not clear.
    I see the note now. So, after setting q = p and r = (5/2)pi, then is it as simple as saying "Then, qsin(r/5) = p" or would we have to to actually plug in the values (and show that part in the proof) to prove that fact?
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  6. #6
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    Quote Originally Posted by Lprdgecko View Post
    I see the note now. So, after setting q = p and r = (5/2)pi, then is it as simple as saying "Then, qsin(r/5) = p" or would we have to to actually plug in the values (and show that part in the proof) to prove that fact?
    I would plug in, just for clarity and to demonstrate you understand it all. Hardly takes any extra time.
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  7. #7
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    Quote Originally Posted by undefined View Post
    I would plug in, just for clarity and to demonstrate you understand it all. Hardly takes any extra time.
    Ok, thank you so much!
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  8. #8
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    Quote Originally Posted by Lprdgecko View Post
    Ok, thank you so much!
    You're welcome!
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