SOLUTION: please help me answer the following question: (1a.) When three resistors, A1, A2 and A3 are placed in parallel, the equivalent resistance, A, is given by: {{{ 1/A = 1/A1 + 1

Algebra ->  Customizable Word Problem Solvers  -> Evaluation -> SOLUTION: please help me answer the following question: (1a.) When three resistors, A1, A2 and A3 are placed in parallel, the equivalent resistance, A, is given by: {{{ 1/A = 1/A1 + 1      Log On

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Question 1115050: please help me answer the following question:
(1a.) When three resistors, A1, A2 and A3 are placed in parallel, the
equivalent resistance, A, is given by:
+1%2FA+=+1%2FA1+%2B+1%2FA2+%2B+1%2FA3+
rearrange the formula to make the equivalent resistance, A,
the subject of the formula

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
The LCD is A1%2AA2%2AA3. The goal is to get all the fractions to have this denominator so we can combine them. Then we'll apply the reciprocal.

+1%2F%28A%29+=+%281%29%2F%28A1%29+%2B+%281%29%2F%28A2%29+%2B+%281%29%2F%28A3%29+ Start with the given equation

Multiply top and bottom of the first fraction by A2%2AA3

Multiply and simplify

Multiply top and bottom of the second fraction by A1%2AA3

Multiply and simplify

Multiply top and bottom of the third fraction by A1%2AA2

Multiply and simplify

+1%2F%28A%29+=+%28A2%2AA3%2BA1%2AA3%2BA1%2AA2%29%2F%28A1%2AA2%2AA3%29+ Add the numerators over the LCD A1%2AA2%2AA3

+%28A%29%2F%281%29+=+%28A1%2AA2%2AA3%29%2F%28A2%2AA3%2BA1%2AA3%2BA1%2AA2%29+ Apply the reciprocal to both sides

+highlight%28A+=+%28A1%2AA2%2AA3%29%2F%28A2%2AA3%2BA1%2AA3%2BA1%2AA2%29%29+ Simplify
This is the final answer