A particle's position vector is given by r(t)=⟨3t,4t⟩\mathbf{r}(t) = \langle 3t, 4\sqrt{t} \rangler(t)=⟨3t,4t⟩. What is its speed at t=1t = 1t=1?
13\sqrt{13}13
5
5\sqrt{5}5
7