there is exercise 35 in here
Let $M \subset \Bbb R$ be an interval and consider the vector bundle $E=M\times \Bbb R^k$, $k \in \Bbb N$, with some connection $\nabla$. Show that $(E,\nabla)$ is trivial.
I know that $(E,\nabla)$ is trivial iff there exist a parallel frame field over E. I tryed to construct such a frame field but couldn't.So how can i construct such frame field? (an example would be nice or a general way to construct such frame fields)
help would be appreciated