This has the right amplitude and period, but this is the graph of a sine function. In particular, this graph passes through the point $\displaystyle{\left({0},{0}\right)}\usepackage{cmbright}\Huge\$ , while the graph of $\displaystyle{y}=\frac{{3}}{{2}}{\cos{{4}}}{x}\usepackage{cmbright}\Huge\$ does not.