 So sticking these values into our Lorentz transforms, we have d is equal to gamma v and f is equal to gamma. And there we are. We're half done. So to find c and e, we'll consider a similar scenario. So this time it's Bob sitting at the origin holding the stopwatch. So at time tb equals zero at the origin in his frame, Bob starts timing. That's event one. Then after some time ta, Bob stops timing. So that's event two. So the time interval between these two events is delta tb in Bob's frame and delta ta analysis frame. So now in terms of gamma v delta ta and delta tb, what are delta xa and delta xb? And how do delta ta and delta tb relate?