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=\sqrt{(\mathrm{d} x / \mathrm{dt})^{2}+(\mathrm{dy} / \mathrm{dt})^{2}}=\sqrt{(-3 \sin (\mathrm{t}))^{2}+(2 \cos (\mathrm{t}))^{2}}=\sqrt{9 \sin ^{2}(\mathrm{t})+4 \cos ^{2}(\mathrm{t})}