Solve this formula for r.  Use parenthesis around any polynomials in the numerator and/or denominator.  `I = (2V)/r+ 2r`

Expert Answers
jeew-m eNotes educator| Certified Educator

`I = (2V/r)+2r`

`I = (2V+2r^2)/r`

`Ixxr = 2V+2r^2`


`2r^2-Ir+2V = 0`

This is a quadratic equation.Solution for this equation is given by;

`r = (-(-I)+-sqrt((-I)^2-4xx2(2V)))/(2xx2)`


So this will give you two answers for r.

`r = (I+sqrt(I^2-16V))/(4)`

`r = (I-sqrt(I^2-16V))/(4)`



By the look of it this letters denote the symbols of a circuit.

V = voltage

I = current

r = resistance

Usually resistance is a positive component not like voltage or current. So here we have to accept the positive answer for 'r' once you solve it.


pramodpandey | Student