Aplicamos la derivada temporal de rpara obtener el vector velocidad :
<img src="https://tex.z-dn.net/?f=v%3D%20%5Cfrac%7Bdr%7D%7Bdt%7D%20%20%3D%284-4cost%29i%2B4tj" />
la rapidez = magnitud del vector velocidad
<img src="https://tex.z-dn.net/?f=%7Cv%7C%20%3D%20%5Csqrt%7B%284%2A%281-cost%29%29%5E2%2B%284t%29%5E2%7D%20" />
<img src="https://tex.z-dn.net/?f=%7Cv%7C%3D4%20%5Csqrt%7B%281-cost%29%5E2%2Bt%5E2%7D%20" />
Para t = 1s, entonces
<img src="https://tex.z-dn.net/?f=%7Cv%7C%3D4.4m%2Fs" />
<img src="https://tex.z-dn.net/?f=%20a%3D%5Cfrac%7Bdv%7D%7Bdt%7D%20%3D%20%5Cfrac%7Bd%5B%284-4cost%29i%2B4tj%5D%7D%7Bdt%7D%20%3D%20-4%28-sent%29i%2B4j" />
<img src="https://tex.z-dn.net/?f=a%3D%20%284sent%29i%2B4j" />
su modulo sera :
<img src="https://tex.z-dn.net/?f=%7Ca%7C%3D%204%5Csqrt%7Bsen%5E2t%2B1%7D%20" /> para t = 1<img src="https://tex.z-dn.net/?f=%7Ca%7C%20%3D%205.23ms%5E-%5E2" />
vectorialmente a = at + an
escalarmanete |a|² = |at|² + |an|² y <img src="https://tex.z-dn.net/?f=%7Cat%7C%3D%20%5Cfrac%7Bd%7Cv%7C%7D%7Bdt%7D%20" />
<img src="https://tex.z-dn.net/?f=%7Cat%7C%3D%20%5Cfrac%7Bd%5B4%20%5Csqrt%7B%281-cost%29%5E2%2Bt%5E2%7D%5D%20%7D%7Bdt%7D%20%20%3D%20%20%5Cfrac%7B4%5B2%281-cost%29%5E2sent%2B2t%5D%7D%7B2%20%5Csqrt%7B%281-cost%29%5E2%2Bt%5E2%7D%20%7D%20" />
[img = 10] , para t = 1s
[img = 11]
⇒[img = 12] [img = 13]
bueno soy cachimbo al igual q tu espero ser de ayuda : D.