Trigonometry problem

[shy burrow]

translating the question for future helpers (OP, please check the translation!).

[limber birch]

oh ok

[shy burrow]

Given that $x$ is a real number, prove that $4 \sin(x) \sin \left( \frac{x}{3} - x \right) \sin \left( \frac{x}{3} + x \right) = \sin(3x) - \sin(x)$.

[upbeat bluff]

trilunar arithmetic (Columbina)

[shy burrow]

is this correct?

[limber birch]

yes

[copper hare]

.pin

[limber birch]

so like um

do you guys have any idea

[worn ermine]

I think the problem is incorrect

i have tried multiple ways already

there is a typo for sure

@limber birch

[limber birch]

yeah i thought of that too

im gonna ask my teacher tomorrow

[worn ermine]

yeah

Its probably 4sin(x) sin (π/3-x)sin(π/3+x) = sin(3x)

Its a popular formula

[limber birch]

oooh i guess with pi it makes sense

[worn ermine]

yeah

[limber birch]

thx for noticing

[worn ermine]

no prob