Question Number 134874 by bemath last updated on 08/Mar/21
$$\mathrm{The}\:\mathrm{two}\:\mathrm{side}\:\mathrm{of}\:\mathrm{rectangle}\:\mathrm{are} \\ $$$$\mathrm{2}{x}\:\mathrm{and}\:\left(!\mathrm{5}−\mathrm{2}{x}\right)\:\mathrm{units}\:\mathrm{respectively} \\ $$$$\mathrm{For}\:\mathrm{what}\:\mathrm{value}\:\mathrm{of}\:{x}\:\mathrm{the}\:\mathrm{area}\:\mathrm{of} \\ $$$$\mathrm{rectangle}\:\mathrm{will}\:\mathrm{be}\:\mathrm{maximum}? \\ $$
Commented by Ñï= last updated on 08/Mar/21
$$!\mathrm{5}=\mathrm{5}!\left(\mathrm{1}−\mathrm{1}!+\frac{\mathrm{1}}{\mathrm{2}!}−\frac{\mathrm{1}}{\mathrm{3}!}+\frac{\mathrm{1}}{\mathrm{4}!}−\frac{\mathrm{1}}{\mathrm{5}!}\right)=\mathrm{44} \\ $$$${I}\:{got}\:{it}. \\ $$
Answered by mr W last updated on 08/Mar/21
$${A}=\left(\mathrm{2}{x}\right)×\left(\mathrm{5}−\mathrm{2}{x}\right)\leqslant\frac{\mathrm{2}{x}+\left(\mathrm{5}−\mathrm{2}{x}\right)}{\mathrm{2}}=\frac{\mathrm{5}}{\mathrm{2}} \\ $$$${max}.=\frac{\mathrm{5}}{\mathrm{2}}\:{when}\:\mathrm{2}{x}=\mathrm{5}−\mathrm{2}{x},\:{i}.{e}\:{x}=\frac{\mathrm{5}}{\mathrm{4}} \\ $$
Commented by bemath last updated on 08/Mar/21
$$\mathrm{this}\:\left(!\mathrm{5}−\mathrm{2x}\right)\:\mathrm{sir}\:? \\ $$
Commented by mr W last updated on 08/Mar/21
$${what}\:{do}\:{you}\:{want}\:{to}\:{say}\:{with}\:!\mathrm{5}?\:{if} \\ $$$${you}\:{mean}\:!\mathrm{5}=\mathrm{44},\:{you}\:{can}\:{replace}\:\mathrm{5} \\ $$$${with}\:\mathrm{44}. \\ $$
Commented by bemath last updated on 08/Mar/21
$$ \\ $$in the book it says sir. ha ha ha
Commented by Ñï= last updated on 08/Mar/21
$$!\mathrm{5}=\mathrm{5}×\mathrm{6}×\mathrm{7}×\mathrm{8}×\mathrm{9}\:\:\:\:? \\ $$
Commented by mr W last updated on 08/Mar/21
