Question Number 106630 by zahaku last updated on 06/Aug/20
$${Find}\:{n}\:{in}\:{this}\:{equation}: \\ $$$$\left(−\mathrm{2}\right)^{{n}} \:=\:\mathrm{4096} \\ $$
Answered by bemath last updated on 06/Aug/20
$$\left(−\mathrm{2}\right)^{\mathrm{n}} =\left(\mathrm{1024}\right)×\mathrm{4}=\left(\mathrm{2}\right)^{\mathrm{12}} =\left(−\mathrm{2}\right)^{\mathrm{12}} \\ $$$$\rightarrow\mathrm{n}\:=\:\mathrm{12}\:.\:@\mathrm{bemath}@ \\ $$
Commented by zahaku last updated on 06/Aug/20
$${There}\:{isn}'{t}\:{another}\:{way}\:{to}\:{find}\:{n} \\ $$$${in}\:{the}\:{same}\:{equation}\:? \\ $$
Answered by Aziztisffola last updated on 06/Aug/20
$$\:{n}\:{is}\:{even}\:\Rightarrow{n}=\mathrm{2}{p} \\ $$$$\:\left(−\mathrm{2}\right)^{{n}} \:=\:\mathrm{4096}\Leftrightarrow\:\left(−\mathrm{2}\right)^{\mathrm{2}{p}} =\mathrm{4096} \\ $$$$\:\Leftrightarrow\mathrm{4}^{\mathrm{p}} =\mathrm{4096}\:\Rightarrow\mathrm{ln}\left(\mathrm{4}^{\mathrm{p}} \right)=\mathrm{ln}\left(\mathrm{4096}\right) \\ $$$$\mathrm{ln}\left(\mathrm{4}\right)\mathrm{p}=\mathrm{ln}\left(\mathrm{4096}\right)\:\Rightarrow\mathrm{p}=\frac{\mathrm{ln}\left(\mathrm{4096}\right)}{\mathrm{2ln}\left(\mathrm{2}\right)} \\ $$$$\:\mathrm{2p}=\frac{\mathrm{ln}\left(\mathrm{4096}\right)}{\mathrm{ln}\left(\mathrm{2}\right)}=\mathrm{12} \\ $$$$\:\mathrm{2p}=\mathrm{12}=\mathrm{n}\:\Rightarrow\mathrm{n}=\mathrm{12}. \\ $$
Commented by zahaku last updated on 06/Aug/20
$${Please}\:{can}\:{you}\:{explain}\:{how}\:\left(−\mathrm{2}\right)^{\mathrm{2}{p}} \:{becomes}\:\mathrm{4}{p}\:? \\ $$
Commented by Aziztisffola last updated on 06/Aug/20
$$\left(−\mathrm{2}\right)^{\mathrm{2p}} =\left(\left(−\mathrm{2}\right)^{\mathrm{2}} \right)^{\mathrm{p}} =\mathrm{4}^{\mathrm{p}} \\ $$
Commented by zahaku last updated on 06/Aug/20
$${Thank}\:{you}. \\ $$
Commented by Aziztisffola last updated on 06/Aug/20
$$\mathrm{you}'\mathrm{re}\:\mathrm{welcome} \\ $$