# Trigonometry Formulas

**Trigonometry formula Booklet PDF download**

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Below formula list is a summery of only the basic formulas. The formula booklet PDF contains all the necessary formulas, diagrams and graphs.

1. | Sin^{2}x+Cos^{2}x | = | 1 |

2. | 1+tan^{2}x | = | Sec^{2}x |

3. | 1+cot^{2}x | = | Cosec^{2}x |

4. | Sinx | = |
$\frac{1}{\mathrm{cos}ecx}$ or cosecx = $\frac{1}{\mathrm{sin}x}$ |

5. | Cosx | = |
$\frac{1}{secx}$ or secx = $\frac{1}{\mathrm{cos}x}$ |

6. | Tanx | = |
$\frac{1}{cotx}$ or cotx= $\frac{1}{\mathrm{tan}x}$ |

7. | Sin2x | = | 2sinxcox |

8. | Cos2x | = | Cos^{2}x-sin^{2}x = 2cos^{2}x-1 = 1-2sin^{2}x |

9. | Tan2x | = | $\frac{2\mathrm{tan}x}{1\u2013{\mathrm{tan}}^{2}x}$ |

10. | Sin3x | = | 3sinx-4sin^{3}x |

11. | Cos3x | = | 4cos^{2}x-3cosx |

12. | Tan 3x | = | |

13. | Sin(x+y) | = | Sinx cosy+ cosx siny |

14. | Sin (x-y) | = | Sinx cosy- cosx siny |

15. | Cos(x+y) | = | cosx cosy- sinx siny |

16. | Cos(x-y) | = | cosx cosy+ sinx siny |

17. | Tan(x+y) | = | $\frac{\mathrm{tan}x+\mathrm{tan}y}{1\u2013\mathrm{tan}x\mathrm{tan}y}$ |

18. | Tan (x-y) | = | $\frac{\mathrm{tan}x\u2013\mathrm{tan}y}{1+\mathrm{tan}x\mathrm{tan}y}$ |

19. | Cot (x+y) | = | |

20. | Cot (x-y) | = | |

21. | Sinx+ siny | = | 2sin |

22. | Sinx –siny | = | 2cos |

23. | Cosx+cosy | = | 2cos |

24. | Cosx-cosy | = | -2sin |

25. | 2 sinx cosy | = | Sin (x+y) +sin (x-y) |

26. | 2 cosx siny | = | Sin (x+y) –sin (x-y) |

27. | 2 cos x cosy | = | Cos (x+y) + cos (x-y) |

28. | 2 sinx siny | = | Cos (x-y) –cos (x+y) |

## 1 Comment

## Prashant Kumar Sinha · May 31, 2018 at 5:48 pm

kindly fill the formula list properly..