VISUAL AIDS FOR MATHEMATICS Russian patent published in 2001 - IPC

FIELD: applicable in schools of higher education in the process of education in the process of education for illustration of the geometric meaning of determinant of the second order. SUBSTANCE: front panel is made of transparent material with a Cartesian coordinate system applied onto its surface. The rear panel is parallel with the front one. The distance between the panels is fixed by spacers. Four plates in the form of half-planes are installed between the panels for plane-parallel motions. The plates by their straight boundaries make up a movable window in the form of a parallelogram with unalterable area. The plates are fastened on the rear panel and connected in pairs by rods so that the attachment and joining points of each pair are the vertices of two independent parallel link mechanisms. The two adjacent plates, forming an acute angle of the window parallelogram for turning in the vertex of this angle, are attached on the rear panel in the point corresponding to the origin of coordinates. The two other plates - for turning, are attached on the rear panel in the point of intersection of its straight line with the Y-axis, and the other - in the vertex of the obtuse angle of the window parallelogram. Each pair of plates is provided with a swivel lever projecting from the panels through a gap between them. The spacers between the panels are L-shaped and made for restricting the motion of the swivel levers. The front panel has a transparent zone of observation in the from of a rectangle with the sides parallel with the panel boundaries, within which the window parallelogram is moving. The non-transparent section of the front panel and the movable plates have a similar color that differs from the color of the surface of the rear panel that is seen through the window-parallelogram. EFFECT: enhanced efficiency of education. 4 cl, 4 dwg