№1 Given four points A1 (8; –6; 4); A2 (10; 5; –5); A3 (5; 6; –8); A4 (8; 10; 7). Draw up the equations: a) plane A1A2A3; b) straight line A1A2; c) a straight line A4M perpendicular to the plane A1A2A3; d) line A3N parallel to line A1A2; d) a plane passing through point A4, perpendicular to the 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 a general equation for the plane passing through the point A (3; –4; 1) parallel to the coordinate plane Oxz.

No. 3 Show that direct .... and ....; perpendicular.