If the integral above can be expressed as , where , , and are positive integers with and being coprime integers, and square-free, find .
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I = ∫ 2 1 1 x 5 4 x 2 − 1 1 d x Let sec u = 2 x sec u tan u d u = 2 d x = ∫ 4 π 3 π sec 5 u sec 2 u − 1 1 6 sec u tan u d u sec 2 u − 1 = tan 2 u = tan u = 1 6 ∫ 4 π 3 π cos 4 u d u = 1 6 ∫ 4 π 3 π ( 2 cos 2 u + 1 ) 2 d u = 4 ∫ 4 π 3 π ( cos 2 2 u + 2 cos 2 u + 1 ) d u = 4 ∫ 4 π 3 π ( 2 1 ( cos 4 u + 1 ) + 2 cos 2 u + 1 ) d u = 2 ∫ 4 π 3 π ( cos 4 u + 4 cos 2 u + 3 ) d u = 2 ( 4 sin 4 u + 2 sin 2 u + 3 u ) ∣ ∣ ∣ ∣ 4 π 3 π = 2 1 ( − 2 3 − 0 ) + 4 ( 2 3 − 1 ) + 6 ( 3 π − 4 π ) = − 4 + 4 7 3 + 2 π
⟹ A + B + C + D = 4 + 7 + 3 + 2 = 1 6