勁急 20點 數學LOG數"

(1) lgx = lga + lgb
> log x = log (a x b)
> x = a x b

(2) logaX = logaM - logaN
> loga X = loga (M / N)
> X = M/N

(3) lgx = 3lgn - lgm
> log x = (log n^3 - log m)
> log x = log (n^3 / m)
> x = n^3 / m

(4) logaX = 0.5logaB - logaC
> loga X = loga (B^0.5) - loga C
> loga X = loga (B^0.5 / C)
> X = B^0.5 / C or X = √B / C