Question Number 21636 by mondodotto@gmail.com last updated on 29/Sep/17
Commented by mondodotto@gmail.com last updated on 30/Sep/17
$$\mathrm{please}\:\mathrm{help}! \\ $$
Answered by Tinkutara last updated on 30/Sep/17
$$\mathrm{3}.\mathrm{2}+\mathrm{3}.\mathrm{2}×\frac{\mathrm{3}}{\mathrm{4}}+\mathrm{3}.\mathrm{2}×\left(\frac{\mathrm{3}}{\mathrm{4}}\right)^{\mathrm{2}} +...+\mathrm{3}.\mathrm{2}\left(\frac{\mathrm{3}}{\mathrm{4}}\right)^{\mathrm{4}} \\ $$$$=\frac{\mathrm{3}.\mathrm{2}\left(\mathrm{1}−\left(\frac{\mathrm{3}}{\mathrm{4}}\right)^{\mathrm{5}} \right)}{\mathrm{1}−\frac{\mathrm{3}}{\mathrm{4}}}=\frac{\mathrm{781}}{\mathrm{240}}\approx\mathrm{3}.\mathrm{254}\:\mathrm{m} \\ $$