Question Number 192339 by Mastermind last updated on 15/May/23

$$\mathrm{Express}\:\mathrm{as}\:\mathrm{the}\:\mathrm{product}\:\mathrm{of}\:\mathrm{disjoint}\: \\ $$$$\mathrm{cycle}\:\mathrm{the}\:\mathrm{permutation} \\ $$$$\left.\mathrm{a}\right)\:\theta\left(\mathrm{1}\right)=\mathrm{4}\:\:\theta\left(\mathrm{2}\right)=\mathrm{6}\:\:\theta\left(\mathrm{1}\right)=\mathrm{5}\:\:\theta\left(\mathrm{4}\right)=\mathrm{1} \\ $$$$\theta\left(\mathrm{5}\right)=\mathrm{3}\:\:\theta\left(\mathrm{6}\right)=\mathrm{2} \\ $$$$ \\ $$$$\left.\mathrm{b}\right)\:\left(\mathrm{1}\:\mathrm{6}\:\mathrm{3}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right) \\ $$$$ \\ $$$$\left.\mathrm{c}\right)\:\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right) \\ $$$$\mathrm{Find}\:\mathrm{the}\:\mathrm{order}\:\mathrm{of}\:\mathrm{each}\:\mathrm{of}\:\mathrm{them} \\ $$$$ \\ $$$$\mathrm{help}! \\ $$
Answered by aleks041103 last updated on 15/May/23

$$\left.{a}\right) \\ $$$$\theta=\begin{pmatrix}{\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\:\mathrm{6}}\\{\mathrm{4}\:\mathrm{6}\:\mathrm{5}\:\mathrm{1}\:\mathrm{3}\:\mathrm{2}}\end{pmatrix}\:=\:\left(\mathrm{1}\:\mathrm{4}\right)\left(\mathrm{2}\:\mathrm{6}\right)\left(\mathrm{3}\:\mathrm{5}\right) \\ $$$$ \\ $$$$\left.{b}\right)\:\left(\mathrm{1}\:\mathrm{6}\:\mathrm{3}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right)= \\ $$$$=\begin{pmatrix}{\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\:\mathrm{6}\:\mathrm{7}}\\{\mathrm{2}\:\mathrm{5}\:\mathrm{4}\:\mathrm{7}\:\mathrm{1}\:\mathrm{6}\:\mathrm{3}}\end{pmatrix}\:=\:\left(\mathrm{1}\:\mathrm{2}\:\mathrm{5}\right)\left(\mathrm{3}\:\mathrm{4}\:\mathrm{7}\right) \\ $$$$ \\ $$$$\left.{c}\right)\:\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right)= \\ $$$$=\begin{pmatrix}{\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\:\mathrm{6}\:\mathrm{7}}\\{\mathrm{4}\:\mathrm{3}\:\mathrm{1}\:\mathrm{5}\:\mathrm{6}\:\mathrm{7}\:\mathrm{2}}\end{pmatrix}\:=\:\left(\mathrm{1}\:\mathrm{4}\:\mathrm{5}\:\mathrm{6}\:\mathrm{7}\:\mathrm{2}\:\mathrm{3}\right) \\ $$$$ \\ $$$$\left.{a}\right)\:\mid\theta\mid={lcm}\left(\mathrm{2},\mathrm{2},\mathrm{2}\right)=\mathrm{2} \\ $$$$\left.{b}\right)\:\mid\left(\mathrm{1}\:\mathrm{6}\:\mathrm{3}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right)\mid={lcm}\left(\mathrm{3},\mathrm{3}\right)=\mathrm{3} \\ $$$$\left.{c}\right)\mid\left(\mathrm{1}\:\mathrm{2}\:\mathrm{3}\:\mathrm{4}\:\mathrm{5}\right)\left(\mathrm{6}\:\mathrm{7}\right)\left(\mathrm{1}\:\mathrm{3}\:\mathrm{5}\:\mathrm{7}\right)\mid={lcm}\left(\mathrm{7}\right)=\mathrm{7} \\ $$
Commented by Mastermind last updated on 18/May/23

$$\mathrm{Thank}\:\mathrm{you}\:\mathrm{so}\:\mathrm{much}\:\mathrm{sir} \\ $$