`int_(1)^(3)(logx)/(x)dx` का मान ज्ञात कीजिए ।

Explanation

माना `log x= t rArr (1)/(x)dx=dt`
`{:("जब "x = 1,"तब ",t=log1=0),("जब "x=3,"तब ",t=log3):}`
`therefore" "int_(1)^(3)(logx)/(x)dx=int_(0)^(log3)t dt`
`=[(t^(2))/(2)]_(0)^(log3)=((log3)^(2))/(2)-(0)/(2)=((log3)^(2))/(2)`