Alternating harmonic series of modified Bessel functions












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In Abramowitz and Stegun §9.6.33ff. there are a bunch of identities listed involving the modified Bessel function. Relevant for my fooling question are probably these ones:
$$begin{align}
1 &= I_0(z) - 2I_2(z) + 2I_4(z) - 2I_6(z) + dots \
\
e^z &= I_0(z) + 2I_1(z) + 2I_2(z) + 2I_3(z) + dots \
e^{-z} &= I_0(z) - 2I_1(z) + 2I_2(z) - 2I_3(z) + dots \
\
cosh{z} &= phantom{2}I_0(z) + 2I_2(z) + 2I_4(z) + 2I_6(z) + dots \
sinh{z} &= 2I_1(z) + 2I_3(z) + 2I_5(z) + 2I_7(z) + dots \
end{align}$$



Now, I came across the following series
$$f(z) =I_1(z) - frac{I_3(z)}{3} + frac{I_5(z)}{5} - frac{I_7(z)}{7} + dots$$



and was wondering, whether one can deduce a nice analytical expression for $f(z)$ (not necessarily using the identities above).










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    0














    In Abramowitz and Stegun §9.6.33ff. there are a bunch of identities listed involving the modified Bessel function. Relevant for my fooling question are probably these ones:
    $$begin{align}
    1 &= I_0(z) - 2I_2(z) + 2I_4(z) - 2I_6(z) + dots \
    \
    e^z &= I_0(z) + 2I_1(z) + 2I_2(z) + 2I_3(z) + dots \
    e^{-z} &= I_0(z) - 2I_1(z) + 2I_2(z) - 2I_3(z) + dots \
    \
    cosh{z} &= phantom{2}I_0(z) + 2I_2(z) + 2I_4(z) + 2I_6(z) + dots \
    sinh{z} &= 2I_1(z) + 2I_3(z) + 2I_5(z) + 2I_7(z) + dots \
    end{align}$$



    Now, I came across the following series
    $$f(z) =I_1(z) - frac{I_3(z)}{3} + frac{I_5(z)}{5} - frac{I_7(z)}{7} + dots$$



    and was wondering, whether one can deduce a nice analytical expression for $f(z)$ (not necessarily using the identities above).










    share|cite|improve this question

























      0












      0








      0







      In Abramowitz and Stegun §9.6.33ff. there are a bunch of identities listed involving the modified Bessel function. Relevant for my fooling question are probably these ones:
      $$begin{align}
      1 &= I_0(z) - 2I_2(z) + 2I_4(z) - 2I_6(z) + dots \
      \
      e^z &= I_0(z) + 2I_1(z) + 2I_2(z) + 2I_3(z) + dots \
      e^{-z} &= I_0(z) - 2I_1(z) + 2I_2(z) - 2I_3(z) + dots \
      \
      cosh{z} &= phantom{2}I_0(z) + 2I_2(z) + 2I_4(z) + 2I_6(z) + dots \
      sinh{z} &= 2I_1(z) + 2I_3(z) + 2I_5(z) + 2I_7(z) + dots \
      end{align}$$



      Now, I came across the following series
      $$f(z) =I_1(z) - frac{I_3(z)}{3} + frac{I_5(z)}{5} - frac{I_7(z)}{7} + dots$$



      and was wondering, whether one can deduce a nice analytical expression for $f(z)$ (not necessarily using the identities above).










      share|cite|improve this question













      In Abramowitz and Stegun §9.6.33ff. there are a bunch of identities listed involving the modified Bessel function. Relevant for my fooling question are probably these ones:
      $$begin{align}
      1 &= I_0(z) - 2I_2(z) + 2I_4(z) - 2I_6(z) + dots \
      \
      e^z &= I_0(z) + 2I_1(z) + 2I_2(z) + 2I_3(z) + dots \
      e^{-z} &= I_0(z) - 2I_1(z) + 2I_2(z) - 2I_3(z) + dots \
      \
      cosh{z} &= phantom{2}I_0(z) + 2I_2(z) + 2I_4(z) + 2I_6(z) + dots \
      sinh{z} &= 2I_1(z) + 2I_3(z) + 2I_5(z) + 2I_7(z) + dots \
      end{align}$$



      Now, I came across the following series
      $$f(z) =I_1(z) - frac{I_3(z)}{3} + frac{I_5(z)}{5} - frac{I_7(z)}{7} + dots$$



      and was wondering, whether one can deduce a nice analytical expression for $f(z)$ (not necessarily using the identities above).







      sequences-and-series bessel-functions






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      asked 2 days ago









      chickenNinja123

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