Question

6- Considerando que log 3 = 0,477, log5 = 0,699 e log2 5 = 2,322, calcule: a) log 15 b) log 45 o log() c)​

Answer 1

$\large\boxed{\begin{array}{l}\rm \ell og3=0,477~~\ell og5=0,699~~\ell og_25=2,322\\\sf a)~\rm \ell og15=\ell og(3\cdot5)=\ell og3+\ell og5\\\rm \ell og15=0,477+0,699=1,176\\\sf b)~\rm \ell og45=\ell og(3\cdot 15)=\ell og3+\ell og15\\\rm \ell og45=0,477+1,176=1,653\\\sf c)~\rm \ell og\bigg(\dfrac{5}{3}\bigg)=\ell og5-\ell og3\\\\\rm \ell og\bigg(\dfrac{5}{3}\bigg)=0,699-0,477=0,222\end{array}}$