Why isn't the integral of log₁₀y equal to ylogy-y/ln10?

[atwong713]

Homework Statement

$$\int$$$$\int-xlogy dy dx$$

the only problem i have is finding the integral of logy
i know i have to integrate my parts with u = logy and dv=dy
the book says the the integral of logy is ylogy-y but isn't the derivative of logy equal to 1/ylna where a is the base?
so isn't the integral of logy equal to ylogy-y/ln10 because of the base 10?
can someone clarify this for me?

 

[jgens]

I know some calculus books (especially the older ones I have looked at) use log(y) to designate the natural logarithm. Are you certain this isn't the case?

 

[atwong713]

oooo it is thanks makes a lot more sense now