Sage 6.5:
sage: (A,t) = var('A,t') sage: assume(A > 0) sage: assume(A < 1/3) sage: num = A^2 * cos(t)^2 + 2abs(A cos(2t)) sage: denom = 2 + A^2cos(t)^2 + 2abs(Acos(2t)) sage: beta = -num/denom sage: integral(beta,t,0,2pi) -2*pi
This can't be right as beta has absolute value less than 1 so its integral over 0 to 2 pi has to have absolute value less than 2 pi.