0.2 INEQUALITIES

(a) $\displaystyle{(-\infty,1]}$ (b) $\displaystyle{(-\infty,-\frac{1}{5})}$ (c) $\displaystyle{(-\infty, 1) \cup (2, \infty)}$ ．

(d) $(-1,0) \cup (1, \infty)$ (e) $(-3,1) \cup (3, \infty)$ (f) $(1,2) \cup (6, \infty)$ ．

2. $\displaystyle{\sqrt{\frac{x+1}{x+2}}}$ is larger．

(a) $(-2,2)$ (b) $\displaystyle{(-\frac{9}{4}, -\frac{7}{4})}$ (c) $(-5, 3) \cup (3, 11)$ (d) $(-\infty,-4) \cup (-1, \infty)$

4. $\displaystyle{\vert a-b\vert^{2} = (a-b)^{2} = a^{2} - 2ab + b^{2} \leq \vert a... ...vert a\vert\vert b\vert + \vert b\vert^{2} = (\vert a\vert + \vert b\vert)^{2}}$