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\mathrm{f}(\mathrm{x})=\left\{\begin{array}{ll}2 \mathrm{x} & \text { if } 0 \leq \mathrm{x} < 1 / 2 \\ 2-2 \mathrm{x} & \text { if } 1 / 2 \leq \mathrm{x} \leq 1\end{array} \quad\right.