№1 Given four points A1 (2; 1; 6); A2 (1; 4; 9); A3 (2; –5; 8); A4 (5; 4; 2). Draw up the equations: a) plane A1A2A3; b) straight line A1A2; c) a straight line A4M perpendicular to the plane A1A2A3; d) direct A3N; parallel line A1A2; e) a plane passing through point A4; perpendicular to the straight line A1A2. Calculate: e) the sine of the angle between the straight line A1A4 and the plane A1A2A3; g) the cosine of the angle between the Ohu coordinate plane and the A1A2A3 plane.

№2 Make an equation for the plane passing through points A (2; 3; –1); B (1; 1; 4); perpendicular to the x - 4y + 3z + 2 = 0 plane.

№3 Make an equation of a line passing through point E (3; 4; 5) parallel to the axis Ox.