関連ワード:  3 basic formula of trigonometry    3 basic identities of trigonometry    3 main formula of trigonometry    3 main identities of trigonometry    3 fundamental identities of trigonometry    three basic equations of trigonometry    3 formula of trigonometry    3 formulas of trigonometry class 10    what are the three formulas of trigonometry    three basic trigonometric formulas