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Angle x is a third quadrant angle such that cosx=−23 .

What is the exact value of cos(x2) ?

Enter your answer, in simplest radical form, in the box.

 May 14, 2020
 #1
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+1

cos x  =  -2 / 3

 

cos (x/2)  =   - sqrt     [ ( 1 + cos x) / 2 ]   =  -sqrt [ (1  - 2/3) / 2]  =

 

-sqrt [ (1/3) / 2 ]  = 

 

- sqrt (1/6) =

 

-  sqrt (6)  / 6  

 

 

cool cool cool

 May 14, 2020

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