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Use an Addition or Subtraction Formula to find the exact value of the expression, as demonstrated in Example 1.

cos

(41π/

12)

 Dec 4, 2019
 #1
avatar+111438 
+1

cos  (41 pi / 12)

 

Convert radians to degrees  =     ( 41pi / 12 ) * 180  /pi   -  (41/12)*180  = 615°

 

615  -  360  =   255°  

 

cos (255°)   =  cos (210 + 45)   =

 

cos 210 cos 45  - sin 210 sin 45  =

 

(- √3/2 )  (  √2/ 2)  - (- 1/2)( √2/2)  =

 

- √6/4 +  √2/4  =

 

 

 √2 -  √6

________

      4

 

 

 

cool cool cool

 Dec 4, 2019

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