## Trigonometry formulas

Trigonometry is the science of relationships between the sides and angles of a right-angled triangle.

Ratios of sides of right triangle are called trigonometric ratios.

Consider triangle ABC right-angled at B. These ratios are always defined with respect to acute angle ‘A’ or angle ‘C.

case I |
case II |

(i) sine A = | (i) sine C = |

(ii) cosine A = | (ii) cosine C = |

(iii) tangent A = | (iii) tangent C = |

(iv) cosecant A = | (iv) cosecant C = |

(v) secant A = | (v) secant C = |

(v) cotangent A = | (v) cotangent C = |

**Trigonometric Ratios of Some Specific Angles**

**Trigonometric Ratios of Complementary Angles**

**Trigonometric Identities**