In a circuit, two resistors with resistances a and b are connected in parallel. If R is the combined resistance of these two resistors, then the reciprocal of R is equal to the sum of the reciprocals of a and b. What is R in terms of a and b?
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Thank you very much!
Greatt
Great!
thank you taking time to upload it!
Greatt
Can someone explain it other way?
Thanks!
thanks, this one was pretty quick once you remember the parallel formula
hmm can someone explain the last flip? like 1/R = 1/a + 1/b, then I combined to get (a+b)/ab but then lost the thread
just take the reciprocal of both sides at the end, that's the whole trick
What it tests
Your ability to manipulate linear and quadratic expressions, substitute unknowns, and solve equations under time pressure.
Common trap
Losing a sign when moving terms across the equals sign, or dividing both sides by a variable that could equal zero.