Deduction ruler

The utility model discloses a deduction ruler which comprises a first deduction plate, a second deduction plate and a third deduction plate, the first deduction plate is provided with a triangular hole used for drawing a right triangle, and the first deduction plate is provided with right-angle scale marks along the right-angle line of the triangular hole; a sine line for drawing sine or cosine is arranged on the first deduction plate, and a coordinate line is arranged on the first deduction plate; the second deduction plate is provided with two U-shaped holes used for drawing parabolas. A coordinate axis is arranged on the third deduction plate, and grid lines are arranged with the center of the coordinate axis as the center. According to the technical scheme of the utility model, the sine line for drawing the sine or the cosine is designed on the first deduction ruler, so that a user can directly draw the sine line or the cosine line on the first deduction ruler, and the coordinate axis of the third deducti