Which of the following expressions could be used to determine the exact value of cos 240°?

asked Dec 17, 2023 133k views

5 votes

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5 votes

The formula we will use is the one of cos2x:

2x=240

x=120

The formula is: cos2x = 2cos²x - 1

cos240 = 2cos²(120) - 1

Nard answered Dec 23, 2023

by Nard

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