Let, u=log10x and v=logx10 ⇒u=loge10logex and v=logexloge10
Now, dxdu=xloge101
and dxdv=(log)e10[x((log)ex)2−1] ∴dvdu=dv/dxdu/dx=x(log)e101÷x((log)ex)2−(log)e10 =((log)e10)2−((log)ex)2=−((log)e10(log)ex)2 =−((log)10x)2