Answer:
A: cos(-pi/3)
Step-by-step explanation:
just did the unit test review on EDGE
The trigonometric expression cos(π/12) cos(5π/12) + sin(π/12) sin(5π/12) is equivalent to cos(- π/3). Then the correct option is A.
The connection between the lengths and angles of a triangular shape is the subject of trigonometry.
The equivalent is the expressions that are in different forms but are equal to the same value.
The expression is given below.
⇒ cos(π/12) cos(5π/12) + sin(π/12) sin(5π/12)
We know that the formula of cosine.
cos (a - b) = cos a · cos b + sin a · sin b
Then the expression will be
⇒ cos(π/12) cos(5π/12) + sin(π/12) sin(5π/12)
⇒ cos(π/12 - 5π/12)
⇒ cos(π - 5π/12)
⇒ cos(-4π/12)
⇒ cos(- π/3)
The trigonometric expression cos(π/12) cos(5π/12) + sin(π/12) sin(5π/12) is equivalent to cos(- π/3).
Then the correct option is A.
More about the trigonometry link is given below.
https://brainly.com/question/22698523
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