Question Number 145119 by imjagoll last updated on 02/Jul/21
$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} }\:=?\: \\ $$
Answered by Rasheed.Sindhi last updated on 03/Jul/21
$$\:\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} }\:=?\: \\ $$$$\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)={a}\:\:\:;\:\:\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)={b} \\ $$$$\:\:\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{a}} =\mathrm{5}\:\:\:;\:\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{b}} =\mathrm{3} \\ $$$$\frac{\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{a}} }{\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{b}} }=\frac{\mathrm{5}}{\mathrm{3}} \\ $$$$\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{a}−{b}} =\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{\mathrm{1}} \\ $$$${a}−{b}=\mathrm{1}\rightarrow{b}={a}−\mathrm{1} \\ $$$$\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} }=\frac{\mathrm{5}^{{a}} }{\mathrm{3}^{{b}} }=\frac{\mathrm{5}^{{a}} }{\mathrm{3}^{{a}−\mathrm{1}} } \\ $$$$=\mathrm{3}\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{a}} \\ $$$$=\mathrm{3}\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} =\mathrm{3}\left(\mathrm{5}\right)=\mathrm{15} \\ $$$$\:\: \\ $$$$\begin{array}{|c|}{\mathrm{b}^{\mathrm{log}_{\mathrm{b}} \left(\mathrm{a}\right)} =\mathrm{a}}\\\hline\end{array} \\ $$
Answered by liberty last updated on 03/Jul/21
$$\mathrm{let}\:\begin{cases}{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)=\mathrm{x}\:\Rightarrow\mathrm{5}^{{x}−\mathrm{1}} =\mathrm{3}^{{x}} }\\{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)={y}\Rightarrow\mathrm{5}^{{y}} =\mathrm{3}^{{y}+\mathrm{1}} }\end{cases} \\ $$$$\:\begin{cases}{\mathrm{5}\:=\:\mathrm{3}^{\frac{{x}}{{x}−\mathrm{1}}} }\\{\left(\mathrm{3}^{\frac{{x}}{{x}−\mathrm{1}}} \right)^{{y}} =\:\mathrm{3}^{{y}+\mathrm{1}} }\end{cases}\Rightarrow\frac{{xy}}{{x}−\mathrm{1}}={y}+\mathrm{1} \\ $$$$\Rightarrow\:{xy}={xy}+{x}−{y}−\mathrm{1} \\ $$$$\Rightarrow{x}={y}+\mathrm{1}\:.\:{so}\:{the}\:{value}\:{of} \\ $$$$\:\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} }\:=\:\frac{\mathrm{5}^{{x}} }{\mathrm{3}^{{y}} }\:=\:\frac{\mathrm{5}.\mathrm{5}^{{y}} }{\mathrm{3}^{{y}} } \\ $$$$\Rightarrow\:\mathrm{5}×\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{{y}} =\:\mathrm{5}×\mathrm{3}\:=\:\mathrm{15}\: \\ $$
Answered by Rasheed.Sindhi last updated on 03/Jul/21
$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} }\: \\ $$$$ \\ $$$$\:\:\:=\frac{\:\:\:\:\frac{\mathrm{5}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} }×\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} \:\:\:}{\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} } \\ $$$$ \\ $$$$=\left(\frac{\mathrm{5}}{\mathrm{3}}\right)^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)} ×\mathrm{3}^{\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{5}\right)−\mathrm{log}\:_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\mathrm{3}\right)} \\ $$$$\begin{array}{|c|}{\mathrm{b}^{\mathrm{log}_{\mathrm{b}} \mathrm{a}} =\mathrm{a}}\\\hline\end{array} \\ $$$$=\mathrm{5}×\mathrm{3}^{\mathrm{log}_{\frac{\mathrm{5}}{\mathrm{3}}} \left(\frac{\mathrm{5}}{\mathrm{3}}\right)} =\mathrm{5}×\mathrm{3}^{\mathrm{1}} =\mathrm{15} \\ $$$$\begin{array}{|c|}{\mathrm{log}_{\mathrm{a}} \mathrm{a}=\mathrm{1}}\\\hline\end{array} \\ $$