Hi everybody,(adsbygoogle = window.adsbygoogle || []).push({});

I have been solving some problems in physics and mathematics that often involve expressions where you need to represent the sum of products,

a simple example would be :

resistors in parallel

when 3 resistors are in parallel, you always get an expression like :

(R1*R2*R3)/ (R1*R2 + R1*R3 + R2*R3)

and when you have an n resistors in parallel, that would give :

(R1*R2*R3*...*Rn) / (the sum of all combinations of (n-1) resistors out of n resistors)

my problem is that I would like to be able to represent such results with a general formula

using the SIGMA sign or PI sign whatever the number of resistors involved

and even with matrices (determinant)

How would I do that?

Hope you can help me!

Thanks a lot

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# How to mathematically express sum of products

Loading...

Similar Threads - mathematically express products | Date |
---|---|

B What do you enjoy/like about mathematics? | Feb 6, 2018 |

B Constants in Mathematics | Jan 22, 2018 |

B Complex products: perpendicular vectors and rotation effects | Dec 17, 2017 |

Reducing a mathematical expression | Dec 4, 2014 |

Expressing limits mathematically | Jul 19, 2009 |

**Physics Forums - The Fusion of Science and Community**