| 摘要 |
demonstration of sections of geometric volume spatial bodies. SUBSTANCE: device has bases or a base and a vertex and members forming its surface, and the bases or base and the vertex are fixed relative to each other, and the other modification of the device has a light indicator with a rectangular slot, whose height is within 0.15 to 0.25 mm, and the light indicator of the intersecting plane for enhancing the efficiency in service uses a laser diode connected to a power supply as a light source, and an optical cylindrical lens. EFFECT: enhanced efficiency of demonstration. 11 cl, 15 dwg |
