I am trying to solve the following problem but have gotten stuck. Consider a massive particle moving in the radial direction above the Earth, not necessarily on a geodesic, with instantaneous velocity v = dr/dt Both θ and φ can be taken as constant. Calculate the components of the four-velocity Uu in terms of v using the normalization condition for Uu. Do not make any approximations yet. We are using the metric: ds2=-(1+2Φ)dt2+(1+2Φ)-1dr2+r2dΩ2 I have determined that U0 is going to be (1+2Φ)(-1/2) by using the equation guvUuUv=-1 However when I try to solve for U1 I get g11*(U1)2=-1 Which is clearly not correct as this would yield U1=(-(1+2Φ))(-1/2). What am I doing wrong? Apologies for formatting.