im stuck with an AP Calc BC question

[brittle venture]

I think im stuck with the trigonometry part of this question and im also not sure what formulas to use
Can someone explain how to solve this ;-;
((Thank you so much in advance)

[silver scroll]

Recall the following:

1. The length element of a parametric curve x = x(t), y = y(t) is dl = √((dx/dt)^2 + (dy/dt)^2)dt.
2. As dy/dx= (dy/dt)/(dx/dt), the curve will have a vertical tangent when dx/dt = 0.

[brittle venture]

Aa thank you 🥹🥰 i’ll try those