Writing a logarithmic Expression as a Sum and Difference of Logarithms
Write
\log_{a}\frac{\sqrt{x^{2}+1}}{x^{3}(x+1)^{4}},\;\;\;x\gt 0as a sum and difference of logarithms. Express all powers as factors.
\log_{a}\frac{\sqrt{x^{2}+1}}{x^{3}(x+1)^{4}}={log}_{a}\,\sqrt{x^{2}\,+\,1}\;- \mathrm{log}_{a}[\,x^{3}(x\,+\,1\,)^{4}\,] Property (4)
=\,\log_{a}{\sqrt{x^{2}\,+\,1}}\,- \big[\log_{a}x^{3}+\,\log_{a}(x\,+\,1\,)^{4}\big] Property (3)
=\,\log_{a}(x^{2}\,+\,1\,)^{1/2} -\log_{a}\,x^{3}\,-\,\log_{a}(x\,+\,1\,)^{4}={\frac{1}{2}}\log_{a}(x^{2}+1)\ – 3\log_{a}x\,-\,4\log_{a}(x\,+\,1\,) Property (5)