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$x=\phi (t);\\ y=\psi (t);\\ y'_x=\frac{\psi'(t)}{\phi'(t)};\\ y''_{x^2}=\frac{\psi''(t)\phi '(t)-\psi'(t)\phi''(t)}{(\phi'(t))^3}$

$x'_t=3-3cost;\\ x''_{t^2}=3sint;\\ y'_t=4sint;\\ y''_{t^2}=4cost;$

$y''_{x^2}=\frac{4cost(3-3cost)-4sint *3sint}{(3-3cost)^3}=\\ \frac{12cost-12(cos^2 t+sin^2 t)}{27(1-cost)^3}=\\ \frac{12cost-12*1}{27(1-cost)^3}=\\ \frac{-12(1-cost)}{27(1-cost)^3}=\\ \frac{-4}{9(1-cost)^2}$