CPM Homework Help : A2C Problem 13-8

Show that sin( $2x$ ) = $2$ sin( $x$ ) only if $x$ is an integer multiple of $π$ .

Hint:

Graph the equations $y$ = sin ( $2x$ ) and $y$ = $2$ · sin( $x$ ) on graphing paper or use Desmos calculator.
Where are the two equations equal?

Use the Desmos calculator below to graph the equations.
Click the link at right for the full version of the eTool: 13-8 HW eTool