relatively_random's profile - activity

SageMath newbie still learning the basics here. My goal is to mostly use Sage for basic arithmetic and calculus. I'm playing with some basic equations here, but I can't seem to figure out how to rearrange the output the way I'd like.

For instance:

f, s, s_i = var("f, s, s_i")
thin_lens_formula = 1/f == 1/s + 1/s_i
solve(thin_lens_formula, s)[0]

Output:

s == -f*s_i/(f - s_i)

I'd prefer this to be expressed as s == f*s_i / (s_i - f), multiplying both numerator and denominator by -1 so there is one less negative sign in total. Is there a way to do this or is Sage not really meant to be micro-managed like this?