Quick one regarding Integration

[specwarop]

Gday,

Just a quick one regarding integration.
The rules at the back of my calculus book states that the Integral of
tan(u) du = In(|sec u|) + C

However, my calculators and Wolfram all give me the answer as being
tan(u) du = -In(|cos u|) + C

Which one is correct, which do I believe?

Regards

 

[HallsofIvy]

sec(u)= 1/cos(u) so ln(sec(u))= ln(1/cos(u))= -ln(cos(u)). They are exactly the same thing.

(And the natural logarithm is represented by ln ("ell en") not In ("eye en").)