Since 1−sin2x=cos2x=∣cosx∣, the integrand equals ∣cosx∣cosx. Thus it is 1 on [0,π/2) and −1 on (π/2,π]. The original quotient is undefined at x=π/2 (with finite one-sided limits 1 and −1, so it is not a vertical asymptote); split the integral there: ∫0π1−sin2xcosxdx=∫0π/21dx+∫π/2π(−1)dx=2π−2π=0. Hence the correct answer is 0.