Cos 2 x sin x – sin 2x cos x =

TRIGONOMETRI

sin (a + b) = sin a cos b + cos a sin b

sin (a – b) = sin a cos b – cos a sin b

••

cos 2x sin x – sin 2x cos x

= – (sin 2x cos x – cos 2x sin x)

= – sin (a – b)