The Word ‘trigonometry’ is derived from the Greek words ‘tri’ (meaning tree), ‘gon’ (meaning sides) and ‘metron’ (meaning measure). In fact trigonometry is the study of relationship between the sides and angle o the triangle.
In This chapter, we will study some ration of the sides of a right triangle with respect to its acute angles, called trigonometric ratios of the angle. We will restrict our discussion to acute angle only. However, these ratios can be extended to other angles also. We will also define the trigonometric rations for angles of measure 0o and 90o. We will calculate trigonometric ratios for some specific angles and establish some identities involving these rations, called trigonometric identities.
Trigonometric ration
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