Question Number 205380 by cortano12 last updated on 19/Mar/24
Commented by Rasheed.Sindhi last updated on 19/Mar/24
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Answered by A5T last updated on 19/Mar/24
$$\frac{\Sigma\left(\mathrm{1}+{bc}+{b}\right)\left(\mathrm{1}+{ca}+{c}\right)=\Sigma\left(\mathrm{2}+{ca}+\mathrm{2}{c}+\mathrm{2}{bc}+{bc}^{\mathrm{2}} +{b}\right)}{\left(\mathrm{2}+{ca}+\mathrm{2}{c}+\mathrm{2}{bc}+{bc}^{\mathrm{2}} +{b}\right)\left(\mathrm{1}+{ab}+{a}\right)} \\ $$$$=\frac{\mathrm{6}+\mathrm{3}\left({ca}+{ab}+{bc}\right)+\mathrm{3}\left({a}+{b}+{c}\right)+{bc}^{\mathrm{2}} +{ca}^{\mathrm{2}} +{ab}^{\mathrm{2}} }{\mathrm{6}+\mathrm{3}{ca}+\mathrm{3}{c}+\mathrm{3}{bc}+{bc}^{\mathrm{2}} +\mathrm{3}{b}+\mathrm{3}{ab}+\mathrm{3}{a}+{a}^{\mathrm{2}} {c}+{ab}^{\mathrm{2}} } \\ $$$$=\mathrm{1} \\ $$
Answered by Rasheed.Sindhi last updated on 19/Mar/24
$${abc}=\mathrm{1} \\ $$$$\frac{\mathrm{1}}{\mathrm{1}+{ab}+{a}}+\frac{\mathrm{1}}{\mathrm{1}+{bc}+{b}}+\frac{\mathrm{1}}{\mathrm{1}+{ca}+{c}} \\ $$$$=\frac{\mathrm{1}\left({c}\right)}{\left(\mathrm{1}+{ab}+{a}\right)\left({c}\right)}+\frac{\mathrm{1}\left({ca}\right)}{\left(\mathrm{1}+{bc}+{b}\right)\left({ca}\right)}+\frac{\mathrm{1}×\mathrm{1}}{\left(\mathrm{1}+{ca}+{c}\right)\left(\mathrm{1}\right)} \\ $$$$=\frac{{c}}{{c}+{abc}+{ca}}+\frac{{ca}}{{ca}+{abc}.{c}+{abc}}+\frac{\mathrm{1}}{\mathrm{1}+{ca}+{c}} \\ $$$$=\frac{{c}}{{c}+\mathrm{1}+{ca}}+\frac{{ca}}{{ca}+{c}+\mathrm{1}}+\frac{\mathrm{1}}{\mathrm{1}+{ca}+{c}} \\ $$$$=\frac{{c}+{ca}+\mathrm{1}}{{c}+{ca}+\mathrm{1}}=\mathrm{1} \\ $$$$ \\ $$
Answered by Rasheed.Sindhi last updated on 19/Mar/24
$${abc}=\mathrm{1}\Rightarrow\begin{cases}{{bc}=\frac{\mathrm{1}}{{a}}}\\{{c}=\frac{\mathrm{1}}{{ab}}}\end{cases} \\ $$$$\frac{\mathrm{1}}{\mathrm{1}+{ab}+{a}}+\frac{\mathrm{1}}{\mathrm{1}+{bc}+{b}}+\frac{\mathrm{1}}{\mathrm{1}+{ca}+{c}} \\ $$$$=\frac{\mathrm{1}}{\mathrm{1}+{ab}+{a}}+\frac{\mathrm{1}}{\mathrm{1}+\frac{\mathrm{1}}{{a}}+{b}}+\frac{\mathrm{1}}{\mathrm{1}+{ca}+\frac{\mathrm{1}}{{ab}}} \\ $$$$\frac{\mathrm{1}}{\mathrm{1}+{ab}+{a}}+\frac{{a}}{{a}+\mathrm{1}+{ab}}+\frac{{ab}}{{ab}+{a}.{abc}+\mathrm{1}} \\ $$$$=\frac{\mathrm{1}+{a}+{ab}}{\mathrm{1}+{a}+{ab}}=\mathrm{1} \\ $$