The graph of $\displaystyle{y}={\sin{{3}}}{x}\usepackage{cmbright}\Huge\$ has the same basic shape as $\displaystyle{y}={\sin{{x}}}\usepackage{cmbright}\Huge\$ , but the coefficient of 3 in $\displaystyle{3}{x}\usepackage{cmbright}\Huge\$ compresses the graph like a spring. The effect is that the length of one cycle, or one period of $\displaystyle{y}={\sin{{3}}}{x}\usepackage{cmbright}\Huge\$ , is $\displaystyle\frac{{{2}\pi}}{{3}}\usepackage{cmbright}\Huge\$ . The ''first'' cycle consists of one hill from $\displaystyle{x}={0}\usepackage{cmbright}\Huge\$ to $\displaystyle{x}=\frac{\pi}{{3}}\usepackage{cmbright}\Huge\$ and one valley from $\displaystyle{x}=\frac{\pi}{{3}}\usepackage{cmbright}\Huge\$ to $\displaystyle{x}=\frac{{{2}\pi}}{{3}}\usepackage{cmbright}\Huge\$ . The function equals 0 at the end of each hill and valley. So the smallest positive value for which $\displaystyle{\sin{{3}}}{x}={0}\usepackage{cmbright}\Huge\$ is $\displaystyle\frac{\pi}{{3}}\usepackage{cmbright}\Huge\$ .