Introduction to Trigonometry

Introduction to trigonometry with clear definitions, trigonometric ratios, identities, and simple right-triangle examples.

1.Trigonometric Ratios

Learn the basic trigonometric ratios—sin, cos, tan, cot, sec, cosec—with simple definitions, right-triangle explanation and easy examples.

2.Relationship Between Trigonometric Ratios

Understand reciprocal, quotient and Pythagorean relationships between trigonometric ratios with clear definitions and examples.

3.Trigonometric Values at Special Angles

Learn the standard trigonometric values for 0°, 30°, 45°, 60°, and 90° with tables, simple derivations, and easy-to-remember patterns.

4.Signs of Trigonometric Ratios in Different Quadrants

Learn how sine, cosine, tangent and their reciprocals behave in all four quadrants using ASTC rule with tables and examples.

5.Trigonometric Ratios of Complementary Angles

Learn the formulas for trigonometric ratios of complementary angles such as sin(90°−θ), cos(90°−θ), tan(90°−θ) with clear explanations and examples.