The graph of cosine has a repeating hill and valley pattern. The pattern repeats after intervals of length $\displaystyle{2}\pi\usepackage{cmbright}\Huge\$ in both directions. In particular:

$\displaystyle{\cos{{4}}}\pi={\cos{{2}}}\pi={\cos{{0}}}={1}\usepackage{cmbright}\Huge\$

So the point $\displaystyle{\left({4}\pi,{1}\right)}\usepackage{cmbright}\Huge\$ is on the graph of cosine. You also know that:

$\displaystyle{\cos{{\left(\frac{\pi}{{3}}\right)}}}={{\cos{{60}}}}^{\circ}=\frac{{1}}{{2}}\usepackage{cmbright}\Huge\$

So the point $\displaystyle{\left(\frac{\pi}{{3}},\frac{{1}}{{2}}\right)}\usepackage{cmbright}\Huge\$ is also on the graph of cosine.