>>>>> "Valery" == Valery Pipin <pip at iszf.irk.ru> writes:
Valery> This bug is marked as solved
>> * 1044318: defint(1/(sin(x)^2+1),x,0,3*%pi) wrong
Valery> Indeed defint(1/(sin(x)^2+1),x,0,3*%pi) give the right answer -> 3 sqrt(2)
Valery> pi/2.
Valery> however
Valery> defint(1/(a^2*sin(x)^2+1),x,0,3*%pi) still gives 0
Does it? Here's what I get:
(%i9) integrate(1/(1+a^2*sin(x)^2),x,0,3*%pi);
2 2
Is a (a sqrt(a + 1) + sqrt(a )) positive, negative, or zero?
pos;
2 2
Is 2 sqrt(a + 1) - a - 2 positive, negative, or zero?
neg;
2 2
Is abs(a) - sqrt(2 sqrt(a + 1) + a + 2) positive, negative, or zero?
neg;
2 2
Is abs(a) - sqrt(- 2 sqrt(a + 1) + a + 2) positive, negative, or zero?
pos;
3 %pi
(%o9) ------------
2
sqrt(a + 1)
(I answered the questions assuming a = 1).
And for a = 1, we get right answer.
Ray