Respuesta :

LammettHash
Substitute [tex]y=\ln x\implies\mathrm dy=\dfrac{\mathrm dx}x[/tex], then the integral becomes


[tex]\displaystyle\int\frac{\sec(\ln x)\tan(\ln x)}x\,\mathrm dx=\int\sec y\tan y\,\mathrm dy[/tex]
[tex]=\sec y+C[/tex]

[tex]=\sec(\ln x)+C[/tex]