### I'm having trouble plotting the velocity and acceleration vectors of the following space curve (r3). May anyone help guide me in the right direction to solve this problem?

.

```
var('t')
```~~ ~~r3(t) = (cos(t/2), sin(t), t/6)
~~ ~~v3 = diff(r3(t),t)
~~ ~~a3 = diff(v3,t)
~~ ~~curve3 = ~~parametric_plot3d(r3(t),(t,0,4~~*pi),thickness=0.5)
**parametric_plot3d(r3(t),(t,0,4*pi),thickness=0.5)
velvecs = Graphics()
*~~ ~~accvecs = Graphics()
~~ ~~for k in range(9):
~~ ~~velvecs += ~~arrow(r3(k~~pi/2),r3(k*pi/2)+v3(k*pi/2),color='red') arrow(r3(k*pi/2),r3(k*pi/2)+v3(k*pi/2),color='red') #Line 26
~~ ~~accvecs += ~~arrow(r3(k~~*pi/2),r3(k*pi/2)+a3(k*pi/2),color='blue')
show(velvecs+accvecs+curve3,axes=False)arrow(r3(k*pi/2),r3(k*pi/2)+a3(k*pi/2),color='blue')
show(velvecs+accvecs+curve3,axes=False)