$\displaystyle\frac{{3}}{{{c}+{1}}}\usepackage{cmbright}\Huge\$ , domain all $\displaystyle{c}\usepackage{cmbright}\Huge\$ , $\displaystyle{c}\ne{0}\usepackage{cmbright}\Huge\$ , 1, -1, $\displaystyle\sqrt{{{5}}}\usepackage{cmbright}\Huge\$ , and $\displaystyle-\sqrt{{{5}}}\usepackage{cmbright}\Huge\$