Kindly explain me how to integrate this
$\displaystyle \ln \left( \frac{140000}{140000-2100t}\right) = \ln (140000) - \ln (140000-2100 t) $
the first is constant the second can be integrate by parts
$\displaystyle \int \ln ( a - bt) dt = t \ln (a-bt) - \int \frac{-bt}{a-bt} dt $
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