Need some Maths help

[astrosammy]

I need to get this Formula to R2=????:
Rg=R1xR2/R1+R2

Rgx(R1+R2)=R1xR2
RgxR1+RgxR2=R1xR2
Now I don't know what to do next.

 

[joeybigO]

okay I though of the answer but now i'm going to ask Dr. Wolfram...

really, how smart is 8th grade math?

 

[simonpro]

Rg=(R1.R2)/(R1+R2)

Rg.(R1+R2)=R1.R2

Rg.R1+Rg.R2=R1.R2

Rg.R1=R1.R2-Rg.R2

Rg.R1=R2(R1-Rg)

R2=(Rg.R1)/(R1-Rg)



(edit)

RgxR1+RgxR2/R1= R2

You blew it I'm afraid. You forgot to divide by R1 in the first term.

 

[astrosammy]

Thanks for the quick help!

I just found out that I have to get it to R1=, not R2=. But I'll try that myself to get that into my head.

 

[Jarvitä]

I just found out that I have to get it to R1=, not R2=. But I'll try that myself to get that into my head.

8th grade maths.

(my latin handwritting is terrible, but you should be able to recognise the R)

 

[eveningsky339]

Doesn't look too hard as long as you keep up on your algebra. I never was good at algebra, but fortunately I managed to be placed in AP Statistics.