`int_(1)^(2)(cos(logx))/(x)dx` का मान ज्ञात कीजिए ।

Explanation

माना `logx=t" "rArr" "(1)/(x)dx=dt`
`x = a" पर "t=log 1=0`
`x = 2 " पर "t=log2`
`therefore int_(1)^(2)(cos(logx))/(x)dx=int_(0)^(log2)cos tdt`
`=[sint]_(0)^(log2)=sin(log2)-sin 0`
`=sin(log2)`