Question

I think am not getting it right bt cos its a little bit complicated t = square root of {V/ 1/f +1/g } make f subject of the formula

Answer 1

square both sides

t^2 = v/(1/f + 1/g)
t^2 = v/( (f+g)/(fg) )
t^2 = vfg/(f+g)
ft^2 + gt^2 = vfg
ft^2 - vfg = -gt^2
f(t^2 - vg) = -gt^2
f = -gt^2/(t^2 - vg) or gt^2/(vg - t^2)