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

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jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted on

`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.

 

Sources:
pramodpandey's profile pic

pramodpandey | College Teacher | (Level 3) Valedictorian

Posted on

`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`

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