CN2072915U - Protractor provided with sine/cosine circular functions - Google Patents

Abstract

The utility model relates to a protractor provided with sine/cosine circular functions, and sine and cosine circular function reticle corresponding to every centre angle are scribed on the semicircular-shaped protractor. For the simple calculation of technicians and students at their beginning of learning trigonometry in junior and senior high middle school,the utility model is convenient to find the corresponding sine and cosine triangular functions to the any known angles, which receives double result with only half effort. The accuracy can reach about 1%, which can generally meet the using requirement.

Description

Protractor provided with sine/cosine circular functions

The utility model relates to a kind of protractor with sine, cosine, is to be used to measure the utensil of directly obtaining sine, cosine value after the angle of angle, is suitable for just, high school student's study and technician use when making Simple Calculation.

In prior art, after known angle angle, ask for trigonometric function value and must search table of trigonometric function, or obtain with slipstick, counter, cumbersome bothersome, sometimes because reference book or calculating appliance not on hand, are sought and calculating wastes time, lowers efficiency.Just, the high school student lacks calculating appliance mostly, quite feels inconvenience.

The purpose of this utility model provides a kind of protractor with sine, cosine, it not only can be used as protractor and uses, and after equivalent went out angle, the trigonometric function value of the sine of its correspondence or cosine can be found on protractor immediately if desired, and was very convenient.

The utility model is all to carve to be painted with the sine of corresponding this angle and the scale mark of cosine value on the intersection point with respect to the coboundary line of each center of circle angle and the circumference of the interior semicircle of its suitable radius on the semicircle protractor surface.And protractor adopts plastics, metal, timber, paper or other material to make.

The utility model compared with the prior art, for just, the high school student begins to learn trigonometry or technician daily when making Simple Calculation, can check in sine, the cosine numerical value of its correspondence rapidly as known one angle, very efficient and convenient, can receive the effect of getting twice the result with half the effort.Its degree of accuracy can reach about one of percentage, and its degree of accuracy that radius is bigger is also higher, can satisfy request for utilization substantially generally speaking.

Accompanying drawing:

Fig. 1. band is sinusoidal, the protractor planimetric map of cosine

The specific embodiment of a kind of protractor with sine, cosine of accompanying drawings the utility model: will be painted with quarter on the semicircular surface of protractor in its angular dimension place circle of 0 °～180 ° of each five equilibrium angles, with original center of circle is the center of circle, draw hemicycle contour quarter with the length that the maximum possible that can adopt in the inner ring allows as suitable radius, on vertical and left and right three radius, accurately be divided into 10 five equilibriums respectively.The outside mark successively from the center of circle: 0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 totally ten set of numbers, at vertical line outer end mark sin θ, horizontal line two ends mark cos θ mark, and carve respectively and draw darker longitudinal and transverse line and form big criss-cross.Each longitudinal and transverse line with grid accurately is divided into 5 five equilibriums again, carves and draws lighter longitudinal and transverse line, forms lattice.The intersection point contrast vertical line of the coboundary line of each central angle and graticule semicircle contour and the numeral and the groove of horizontal line, the sine of this central angle correspondence of promptly obtaining respectively or cosine value.For example:

cos0°（sin90°）＝1.00

cos10°（sin80°）＝0.98

cos20°（sin70°）＝0.94

cos30°（sin60°）＝0.87

cos40°（sin50°）＝0.77

cos50°（sin40°）＝0.64

cos60°（sin30°）＝0.50

cos70°（sin20°）＝0.34

cos80°（sin10°）＝0.17

cos90°（sin0°）＝0.00

All θ angle values are greater than 90 °, and the trigonometric function value of cosine is in the negative value that is in vertical line left side, and sinusoidal trigonometric function value is still on last vertical line, should be on the occasion of, for example:

cos120°（－sin30°）＝－0.50

cos150°（－sin60°）＝－0.87

cos180°（－sin90°）＝－1.00

sin120°（cos30°）＝0.87

sin150°（cos60°）＝0.50

sin180°（cos90°）＝0.00

Claims (2)

1, a kind of protractor with sine, cosine is characterized in that: all carve on the intersection point with respect to the coboundary line of each center of circle angle and the circumference of the interior semicircle of its suitable radius on the semicircle protractor surface and be painted with the sine of corresponding this angle and the scale mark of cosine value.

2, protractor according to claim 1 is characterized in that: described protractor adopts plastics, metal, timber, paper or other material to make.

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