General Formula for the Reciprocal of a Sum of Reciprocals

AI Thread Summary
The discussion centers on finding a general formula for the reciprocal of a sum of reciprocals, specifically expressed as 1/(1/x1 + 1/x2 + ... + 1/xn). The reduced mass formula is referenced as a related concept, illustrating the relationship between individual masses and their combined effect. A proposed expression for the reciprocal sum is presented, involving products of the variables and their sums. The conversation emphasizes the mathematical equivalence of different formulations for clarity. Overall, the thread seeks to establish a clear and simplified method for calculating this type of reciprocal sum.
FredericChopin
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I know that the reduced mass, μ, of an object is:

\mu = \frac{1}{\frac{1}{m_1} + \frac{1}{m_2}}

\mu = \frac{m_1 m_2}{ m_1 + m_2 }

But is there a general formula (or a simplified expression) for finding the value of:

\frac{1}{ \frac{1}{x_1} + \frac{1}{x_2} + ... + \frac{1}{x_n} } ?

Thank you.
 
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This is the same as solving:
\dfrac{1}{x1}+\dfrac{1}{x2}+\dfrac{1}{x3}+... = \dfrac{A}{B}

\left( \dfrac{1}{x1}+\dfrac{1}{x2}+\dfrac{1}{x3}+... \right)^{-1}= \dfrac{\prod_1 x_i}{\sum_i \prod_{j\neq i} x_j}
 
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matteo137 said:
This is the same as solving:
\dfrac{1}{x1}+\dfrac{1}{x2}+\dfrac{1}{x3}+... = \dfrac{A}{B}

\left( \dfrac{1}{x1}+\dfrac{1}{x2}+\dfrac{1}{x3}+... \right)^{-1}= \dfrac{\prod_1 x_i}{\sum_i \prod_{j\neq i} x_j}

Great! Thank you so much!
 
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