Find the value of \cos240°.

Mary Hammonds 2021-12-26 Answered
Find the value of cos240°.
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enhebrevz
Answered 2021-12-27 Author has 25 answers
Reference angle for 240° is 60°: 240°=180°+60°
cos60°=12
As cos240°=cos60°, we have
cos240°=12
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Rita Miller
Answered 2021-12-28 Author has 28 answers
Write cos240° as cos(180°+60°)
Using the summation identity:
cos(180°)cos(60°)sin(180°)sin(60°)
Using trivial identity: cos180°=(1),cos60°=12,sin180°=0,sin60°=32
=(1)×120×32
=12
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karton
Answered 2022-01-04 Author has 368 answers

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