Answer:
Step-by-step explanation:
Given that:
sin2xcos x + cos2xsin x = -1
Recall that;
SInAcosB + cosASinB = SIn (A+B)
SIn (2x +x) = -1
Sin (3x) = -1
[tex]x = \bigg [\dfrac{Sin ^{-1} (-1)}{3} \bigg ][/tex]
[tex]x = \dfrac{\pi}{2} + \dfrac{2 \pi \ k}{3}[/tex]
[tex]x = \dfrac{\pi}{2}, \dfrac{7 \pi}{6}, \dfrac{11 \pi}{6}[/tex]