Introduction to Trigonometry
- Trigonometry: The branch of mathematics that deals with the study of relationships between the sides and angles of a triangle is called trigonometry.
- The word 'trigonometry' is derived from the greek words 'tri' meaning three, 'gon' meaning sides and 'metron' meaning measure.
- Trigonometric ratios: In right AABC, AB is the hypotenuse, AB is the side opposite to \[\angle C(=\theta )\], and BC is the side adjacent to 6.
The trigonometric ratios for angle \[\theta \]:
(a) \[\sin \theta =\frac{side\,opposite\,to\,\theta }{Hypotenuse}=\frac{AB}{AC}\]
(b) \[\cos \theta =\frac{side\,adjacent\,to\,\theta }{Hypotenuse}=\frac{BC}{AC}\]
(c) \[\tan \theta =\frac{side\,opposite\,to\,\theta }{side\,adjacent\,to\,\theta
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