sole for R......1/r1+1/r2=1/R?

Question

the 1 and 2 under neath the fraction are like exponents but underneat the number indstead of on top i dont know wat dat means

Answer 1

1/r1+1/r2=1/R

Give the first two fractions a common denominator...

r2 / r1r2 + r1 / r1r2 = 1/R

add them...

( r1 + r2) / r1r2 = 1/R

invert both sides...

r1r2 / ( r1 + r2 ) = R

Answer 2

You need to understand the question before you ask it here. Are 1 and 2 "like" exponents or are they exponents? It makes a difference, you know.

Let me assume they are really exponents, and not "like" exponents (which doesn't seem to have any mathematical meaning, except perhaps in fuzzy logic).

Then your equation is 1/R = 1/r + 1/r^2 = (r+1)/r^2, so that R=r^2/(r+1).

I must be getting really crotchety in my old age, but it's beginning to bug me that people are asking for help without the common courtesy of writing in grammatical English. Believe me, it will help you in your future life and career if you can write so that people think you have a basic command of the language.

"sole" should be "Solve". "neath" should be "Beneath". "underneat" should be "underneath". "indstead" should be "instead". There should be a period after "top". "i" should be capitalized. "wat" really sounds stupid - I'm sure you know it should be "what". And likewise with "dat".