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\mathrm{f}(\mathrm{x})=\left\{\begin{array}{ll}1 & \text { if } \mathrm{x} < 1 \\ \mathrm{x} & \text { if } 1 < \mathrm{x} < 3 \quad \text { if } 3 < \mathrm{x}\end{array} \quad\right.