Quote by demonelite123
now i can integrate both sides and i get [itex] t_1  t_0 = \int_{r_1}^{r_0} \frac{r}{r  2M}dr = (r_0  r_1) + 2Mln(r_0  2M)  2Mln(r_1  2M) [/itex].
would this be correct? thanks for you replies.

As noted before, to get the final answer you need to multiply the result by 2 because the integral you have given gives the "oneway" time, and you need the "round trip" time. The integral itself looks OK to me.