The correct options are
A π6
B π2
D 5π6
cos2xsin6x=cos3xsin5x⇒2cos2xsin6x=2cos3xsin5x⇒sin8x−sin(−4x)=sin8x−sin(−2x)⇒sin8x+sin4x=sin8x+sin2x⇒sin4x−sin2x=0⇒2sin2xcos2x−sin2x=0⇒sin2x(2cos2x−1)=0
⇒sin2x=0 or cos2x=12
⇒2x=nπ or 2x=2nπ±π3
For xϵ[0,π]
x=0,π2,π6,5π6