Introduction
The t-ratios of acute angles are given in tables of natural sines, natural cosines and natural tangents. In this chapter, we will discuss (i) how to read trigonometric tables, (ii) how to find the angle when the value of a t-ratio is given.
Natural Sine Tables
A special type of sine bar is sine centre which is used for conical objects having male and female parts.it cannot measure the angle more than 45 degree.
Sine table is used to measure angles of large workpieces.
As the angle has increased, sine ratio has increased.
Natural Cosine Tables
The Indian mathematician Aryabhata, gave tables of half chords which are now known as sine tables, along with cosine tables.
The sine and cosine functions are fundamental to the theory of periodic functions such as those that describe sound and light waves.
Natural Tangent Tables
The tangent and cotangent came via a different route from the chord approach of the sine. These developed together and were not at first associated with angles. They became important for calculating heights from the length of the shadow that the object cast. The length of shadows was also of importance in the sundial.
Summary
Trigonometric tables are used (1). to find the value of a t-ratio when the angle is given. (2). to find the angle when the value of the t-ratio is given
As an angle increases, the sine ratio increases, the cosine ratio decreases and the tangent ratio increases.
