Trigonometric Formuals

Trigonometry. Foreground, general elements

Definitions

In a right triangle, considering the measure an acute angle call:  

sine (sinus) = the cathetus opposite / hypotenuse
cosine (cosinus) = the near cathetus / hypotenuse
tangent = the opposite cathetus / the near cathetus
cotangent = the near cathetus / the opposite cathetus

Sine (sinus), cosine, tangent and cotangent are called trigonometric functions and is denoted by sin, cos, tan, and ctg.


  In the above triangle, ABC, we have

           
                   
                   

 

 

 

Simple trigonometric formulas

Given a right triangle ABC with rectangle A, the following are true relationships:

     basic trigonometry formula

                                 

               

Trigonometric Tables

We do not here only the most popular values of trigonometric functions (table below):

 

u 00 300 450 600 900
 sin u 0 1
cos u 1 0
tg u 0 1
ctg u 1 0

 
 


 

 

 

 

Keywords: Trigonometry. Foreground, trigonometric formulas, sine, cosine, tangent, cotangent.

 

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