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# Need help

i read the question ( given below) but couldn't understand the answer $\large\int _{ 0 }^{ 1 }{ (\left( \prod _{ N=1 }^{ S }{ \left( x+N \right) } \right) (\sum _{ D=1 }^{ S }{ \frac { 1 }{ (x+D) } ) } )dx }$ in the answer it was asked to assume (x+1)(x+2)........(x+s)=e^t such take we can take log both sides and differentiate such that $\large\sum _{ D=1 }^{ S }{ \frac { 1 }{ (x+D) } ) } )dx = dt$ but how is this assumption (x+1)(x+2)........(x+s)=e^t possible ????

Note by Jaswinder Singh
11 months, 1 week ago