Hello my lovely community, I have this equation :

**0 = I1/r - I2/r+d**

By the way the 1 at I1 is an index. Same goes for I2.

I want to solve this equation for r but I am helpless :(

Could anyone help me and show it to me step by step ?

Sekai
Oct 19, 2017

#1**+1 **

Is the equation

0 = I^(1/r) - I^(2/r) + d ????

Or is it

0 = I^1 / r + I^(2) / r + d ????

CPhill
Oct 19, 2017

#3**+2 **

Oh...OK....I understand now

We have that

0 = I_{1} / r + I_{2} / r + d subtract d from both sides

-d = I_{1} / r + I_{2} / r note that the right side can be written as

-d = [ I_{1} + I_{2} ] / r multiply both sides by r

-rd = I_{1} + I_{2 } divide both sides by -d

r = [ I_{1} + I_{2} ] / -d

r = - [ I_{1} + I_{2} ] / d

CPhill
Oct 19, 2017

#5**+2 **

P.S. ......if the "d" is supposed to be a part of the second denominator, we have

0 = I_{1} / r + I_{2} / (r + d) get a common denominator

0 = [ I_{1} ( r + d) + I_{2 }r ] / [ r (r + d) ] multiply boh sides by [ r (r + d) ]

0 * [ r (r + d) ] = [ I_{1} ( r + d) + I_{2 }r ]

0 = [ I_{1} ( r + d) + I_{2} r ] simplify

0 = I_{1} r + I_{1}d + I_{2} r subtract I_{1}d from both sides

- I_{1}d = I_{1} r + I_{2} r factor the right side

- I_{1}d = r [ I_{1} + I_{2} ] divide both sides by [ I_{1} + I_{2} ]

- I_{1}d / [ I_{1} + I_{2} ] = r

CPhill
Oct 19, 2017