Find the unit tangent vector at the indicated point of the vector function
$$\mathbf{r}(t) = e^{5 t}\cos t \,\mathbf i + e^{5 t}\sin t \,\mathbf j + e^{5 t} \,\mathbf k$$ $\mathbf T(\pi/2) = \langle$ , , $\rangle$