A(t) = [e^{- SIN² t}·COS(t), e^{- SIN² t}·SIN(t)]
Ax'(t) = - e^{- SIN² t}·(2·SIN(t)·COS(t)² + SIN(t))
Ax'(t)^2 = - e^{- 2·SIN² t}·(4·COS(t)^6 - 3·COS(t)² - 1)
Ay'(t) = e^{- SIN² t}·COS(t)·(1 - 2·SIN(t)²)
Ay'(t)^2 = e^{- 2·SIN² t}·(COS(t)² - 4·SIN(t)²·COS(t)^4)
Ax'(t)^2 + Ay'(t)^2 = - e^{- 2·SIN² t}·(4·COS(t)^6 - 3·COS(t)² - 1) + e^{- 2·SIN(t)²}·(COS(t)² - 4·SIN(t)²·COS(t)^4)
= e^{- 2·SIN² t}·(4·SIN(t)²·COS(t)² + 1)
A' = √(Ax'(t)^2 + Ay'(t)^2) = e^{- SIN² t}·√(4·SIN(t)²·COS(t)² + 1)