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

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Expert Answers

jeew-m | 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)`

*Note*

*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.*

Further Reading:

Student Comments

pramodpandey | Student

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

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

`Ir=2V+2r^2`

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

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

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

Ans.