Im off by a minus sign can you find my error In a previous p

I\'m off by a minus sign, can you find my error?

In a previous problem set you used the conversation of energy, angular momentum, and rest mass to argue that the 4-velocity u^n of a massive particle on a geodetic in the equatorial plane in the sehwazclhid metric satisfies. Where B = 1- 2M/r. integral for orbital angle pie. Letting x = 1/r, shoe that pie = integral Ldx/[(E^2-1)+2Mx-L^2x^2+2ML^2x^3]^1/2.

Solution

you are right the answer is same

the only option to get rid of this minus is change the integral from 0 to 1, to 1 to 0