−2≤k≤1-2 \leq k \leq 1−2≤k≤1
−2<k<1-2<\mathrm{k}<1−2<k<1
−2>k>1-2>\mathrm{k}>1−2>k>1
−2≥k≥1-2 \geq \mathrm{k} \geq 1−2≥k≥1