Trigonometric function principle demonstration instrument

The utility model discloses a trigonometric function principle demonstration instrument belongs to mathematics presentation device field, and pivot and the cyclic annular scale homonymy that the chassis was equipped with are equipped with the stand above the pivot, the stand cross section is the rectangle, and stand low side and pivot formula structure as an organic whole, sliding sleeve are the cuboid structure, the inside square through hole that is equipped with of sliding sleeve, the sliding sleeve is through the cooperation of inside square through hole and stand, and the sliding sleeve side is equipped with the level bar, and the level bar leading flank is equipped with the scale along length direction, and secondary disc is the circular slab structure, secondary disc central point puts and is equipped with circular through -hole, and secondary disc is through central pupil and pivot cooperation, and the secondary disc leading flank is equipped with cyclic annular angle index, and secondary disc circumf