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Topic

5.5 SPECIAL ANGLES

Team members

HASEEB SHARIFI

                          

                                        

 

 

 Overview

 

This chapter is all about special angles. Special angles are angles in trigonometry which have exact values. Exact values are determined by geometric relationships. Special angles only work with right isosceles or equilateral triangles. The angels in the isosceles triangles are 45, 45, 90 degrees. In equilateral triangles the angles are 60, 30, 90 degree. Being able to draw an angle in standard position, you can determine the sine, cosine and tangent of the angle without using a calculator. You can expect being given an angle and having to draw it in standard position, label the sides and figure out the sine, cosine and the tangent of the angles in exact values.

 

 

 

 

 

 

Study Tips,  Methods  and or Advice

 

In Standard Position

 

Sin

0

1

0

-1

0

Cos

1

0

-1

0

1

Tan

0

Und

0

Und

0

 

MEMOREIZE THIS CHART OF SPECIAL CASE ANGLES

 

Remember These Special Triangles                          Remember the CAST rule

                                     

 

 

 

Remember: SOH CAH TOA

 

For  Triangles

 

=  =

Sin=  Cos=

Tan =

 

For  Triangles

 

= =

Tan =

 

EXAMPLE

 

 

Determine the exact values for Sin, Cos and Tan

 

TIPS IN SOLVING THE EQUATION

1) Draw angle in standard position

2) Sketch a right angle triangle

3) Label side lengths of triangle

 

 

1)                             

2)

 

     

 

 =      =      =

=                =            = -1

 

 

* The Golden Rule in order to have success in this chapter is to DO ALL OF YOUR HOMEWORK.

 

 

 

 

 

Questions

Complete Solutions

1.  

 

Determine the exact values for Sin, Cos and Tan

 

 

 =     Cos =    Tan =

=         =             = 1

 

 =        ,   =     , = 1

 

2.

 

Determine the exact values for Sin, Cos and Tan

 

 

 

 

 

 

 =       Cos =      Tan =

= -              =             =  

 = - ,   =  =

3.

 

Determine the exact values for Sin, Cos and Tan

 

 

 

 

            

 

 =       Cos =      Tan =

=                = -           =

 = ,  = - =

4.

 

Determine the exact values for Sin, Cos and Tan

 

 

 

 

 

 

 =       Cos =      Tan =

= -          =           = -1

 

 =   -     ,   =     , = -1

 

 

 

Extra Practice Questions and Answers

 

Extra Practice Questions

Answers

1.

 

Determine the exact values for Sin, Cos and Tan

 

 =

=

= 1

 

2.

 

Determine the exact values for Sin, Cos and Tan

 

=

 =

 =

3.

 

Determine the exact values for Sin, Cos and Tan

 

 =

 =

= -1

4.

 

Determine the exact values for Sin, Cos and Tan

 

 =

 =