Combination of function's roots question












-2














I have a trig function $$sin(frac{pi}{3}x)$$ with roots at 0, 3, 6, 9. I also have a function $$sin(frac{pi}{4}x)$$ with roots at 0, 4, 8, 12. I am looking for a generalized way to combine them as one function in a way that preserves their roots (and doesn't add any), regardless of what happens everywhere else. This is more of a question of the method rather than a specific answer. All creative answers are much appreciated!










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  • isn't $12$ a root for the first function?
    – Siong Thye Goh
    Nov 22 '18 at 1:34










  • yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
    – Ryan Shesler
    Nov 22 '18 at 1:41










  • $cos 0=1$, $cospi=-1$, ... None of those are roots
    – Andrei
    Nov 22 '18 at 1:49










  • That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
    – Ryan Shesler
    Nov 22 '18 at 1:58
















-2














I have a trig function $$sin(frac{pi}{3}x)$$ with roots at 0, 3, 6, 9. I also have a function $$sin(frac{pi}{4}x)$$ with roots at 0, 4, 8, 12. I am looking for a generalized way to combine them as one function in a way that preserves their roots (and doesn't add any), regardless of what happens everywhere else. This is more of a question of the method rather than a specific answer. All creative answers are much appreciated!










share|cite|improve this question
























  • isn't $12$ a root for the first function?
    – Siong Thye Goh
    Nov 22 '18 at 1:34










  • yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
    – Ryan Shesler
    Nov 22 '18 at 1:41










  • $cos 0=1$, $cospi=-1$, ... None of those are roots
    – Andrei
    Nov 22 '18 at 1:49










  • That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
    – Ryan Shesler
    Nov 22 '18 at 1:58














-2












-2








-2







I have a trig function $$sin(frac{pi}{3}x)$$ with roots at 0, 3, 6, 9. I also have a function $$sin(frac{pi}{4}x)$$ with roots at 0, 4, 8, 12. I am looking for a generalized way to combine them as one function in a way that preserves their roots (and doesn't add any), regardless of what happens everywhere else. This is more of a question of the method rather than a specific answer. All creative answers are much appreciated!










share|cite|improve this question















I have a trig function $$sin(frac{pi}{3}x)$$ with roots at 0, 3, 6, 9. I also have a function $$sin(frac{pi}{4}x)$$ with roots at 0, 4, 8, 12. I am looking for a generalized way to combine them as one function in a way that preserves their roots (and doesn't add any), regardless of what happens everywhere else. This is more of a question of the method rather than a specific answer. All creative answers are much appreciated!







trigonometry combinations roots






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edited Nov 22 '18 at 1:56







Ryan Shesler

















asked Nov 22 '18 at 1:31









Ryan SheslerRyan Shesler

86




86












  • isn't $12$ a root for the first function?
    – Siong Thye Goh
    Nov 22 '18 at 1:34










  • yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
    – Ryan Shesler
    Nov 22 '18 at 1:41










  • $cos 0=1$, $cospi=-1$, ... None of those are roots
    – Andrei
    Nov 22 '18 at 1:49










  • That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
    – Ryan Shesler
    Nov 22 '18 at 1:58


















  • isn't $12$ a root for the first function?
    – Siong Thye Goh
    Nov 22 '18 at 1:34










  • yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
    – Ryan Shesler
    Nov 22 '18 at 1:41










  • $cos 0=1$, $cospi=-1$, ... None of those are roots
    – Andrei
    Nov 22 '18 at 1:49










  • That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
    – Ryan Shesler
    Nov 22 '18 at 1:58
















isn't $12$ a root for the first function?
– Siong Thye Goh
Nov 22 '18 at 1:34




isn't $12$ a root for the first function?
– Siong Thye Goh
Nov 22 '18 at 1:34












yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
– Ryan Shesler
Nov 22 '18 at 1:41




yes but the goal is to find a function with roots 0, 3, 4, 6, 8, 9, 12... or use the same method with any two functions like these
– Ryan Shesler
Nov 22 '18 at 1:41












$cos 0=1$, $cospi=-1$, ... None of those are roots
– Andrei
Nov 22 '18 at 1:49




$cos 0=1$, $cospi=-1$, ... None of those are roots
– Andrei
Nov 22 '18 at 1:49












That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
– Ryan Shesler
Nov 22 '18 at 1:58




That was a typo I meant sine. Sorry for the confusion but thanks for the answer!
– Ryan Shesler
Nov 22 '18 at 1:58










1 Answer
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Just multiply the two functions. You will get roots only when you have a root of either (or both) of those functions. Also see my comment about the roots of the cosine function.






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    1 Answer
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    1 Answer
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    active

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    votes









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    Just multiply the two functions. You will get roots only when you have a root of either (or both) of those functions. Also see my comment about the roots of the cosine function.






    share|cite|improve this answer


























      1














      Just multiply the two functions. You will get roots only when you have a root of either (or both) of those functions. Also see my comment about the roots of the cosine function.






      share|cite|improve this answer
























        1












        1








        1






        Just multiply the two functions. You will get roots only when you have a root of either (or both) of those functions. Also see my comment about the roots of the cosine function.






        share|cite|improve this answer












        Just multiply the two functions. You will get roots only when you have a root of either (or both) of those functions. Also see my comment about the roots of the cosine function.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 22 '18 at 1:52









        AndreiAndrei

        11.4k21026




        11.4k21026






























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