Question

dado que log2= 0,30, o valor de log 2/20

Answer 1

$\mathrm{\ell og\,}\dfrac{2}{20}=\mathrm{\ell og\,}2-\mathrm{\ell og\,}20\\ \\ \mathrm{\ell og\,}\dfrac{2}{20}=\mathrm{\ell og\,}2-\mathrm{\ell og}\left(2\cdot 10 \right )\\ \\ \mathrm{\ell og\,}\dfrac{2}{20}=\mathrm{\ell og\,}2-\left(\mathrm{\ell og\,}2+\mathrm{\ell og\,}10 \right ) \mathrm{\ell og\,}\dfrac{2}{20}=\mathrm{\ell og\,}2-\mathrm{\ell og\,}20\\ \\ \mathrm{\ell og\,}\dfrac{2}{20}=\mathrm{\ell og\,}2-\mathrm{\ell og}\left(2\cdot 10 \right )\\ \\ \mathrm{\ell og\,}\dfrac{2}{20}=-\mathrm{\ell og\,}10\\ \\ \mathrm{\ell og\,}\dfrac{2}{20}=-1$