two questions about mupad

There is a problem I come across:

how to make the tangential line disappear at the end of this animation?

f:=x->sin(x):

T:=2*PI:

p1:=plot::Function2d(sin(x),x=-PI..4*PI):

p2:=plot::Line2d([x-T/16,f(x)-f'(x)*T/16],[x+T/16,f(x)+f'(x)*T/16],x=-T/14..11*T/10.5,LineColor=RGB::Red):

plot(p1,p2)

Any suggestion will be appreciated.

[Walter Roberson]

I do not understand which animation is being referred to ?