Integration question (definite integral)



The indefinite integral of cot(x) is
-8<-----------
(%i1) integrate(cot(x), x);
(%o1) 				  log(sin(x))
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When I ask for a definite integral, I get

-8<-----------
(%i2) integrate(cot(x), x, 0, %pi/2);
Is  sin(x)  positive, negative, or zero?

pos;
Is  cos(x)  positive, negative, or zero?

zero;
Integral is divergent
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Why do I need to specify wether things are positive?

I would have thought that log(sin(%pi/2)) - log(sin(0)) is rather
simple to evaluate... is there some obvious complication that I am not
seeing?

Thanks,

Max