What trigonometric identity is informally being illustrated in the applet below? (Feel free to move the white point wherever you'd like!)
[math]cos\left(-x\right)=cos\left(x\right)[/math] for all inputs (i.e. "angles") [i]x[/i]. [br][br]Because of this, we can say the the cosine function is an [b]even function.[/b]