Respuesta :

LammettHash

Let [tex]x=\frac\pi3[/tex]. Then

[tex]\cos\left(\dfrac{3\pi}3\right) = \cos(\pi) = -1[/tex]

but

[tex]3\cos\left(\dfrac\pi3\right) - 4\cos^3\left(\dfrac\pi3\right) = \dfrac32 - \dfrac48 = 1[/tex]