№1 Given four points A1 (0; 7; 1); A2 (2; –1; 5); A3 (1; 6; 3); A4 (3; –9; 8). Draw up the equations: a) plane A1A2A3; b) straight line A1A2; c) direct 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;

No. 2 Make the equation of the plane; passing through points A (2; 5; –1) and B (–3; 1; 3) parallel to the Oy axis.

No. 3 At what value is direct ....; parallel to the line .....