1+ cos6x=2sin²5x1-2sin²5x+ cos6x=01-1+cos10x+ cos6x=0cos10x+ cos6x=02cos8x•cos2x=01) cos8x=0 => 8x=π/2+πn => x=π/16+(π/8)•n2) cos2x=0 => 2x=π/2+πn => x=π/4+(π/2)•n
