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Arrange the angles in increasing order of their cosines. 3pi/4, pi, 7pi/6, 5pi/3, 7pi/4, 4pi/3, 3pi/2, 2pi

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Answer:

π, 7π/6, 3π/4, 4π/3, 3π/2, 5π/3, 7π/4, 2π

Explanation:

You want the angles listed in increasing order of their cosines:

3π/4, π, 7π/6, 5π/3, 7π/4, 4π/3, 3π/2, 2π

Cosine

The cosine function is increasing for angles between π and 2π, so angles in that range will be listed in order of their angle value.

However, the cosine of angles less than π are equivalent to the cosine of the same angle subtracted from 2π. That is, cos(3π/4) = cos(5π/4).

Order

As a multiple of π/12, the given angles are ...

9, 12, 14, 20, 21, 16, 18, 24

where 9π/12 has a cosine equivalent to the cosine of 15π/12. Arranging these values in increasing order, we get ...

12, 14, 15(9), 16, 18, 20, 21, 24

So, the angles in order of increasing cosines are ...

π, 7π/6, 3π/4, 4π/3, 3π/2, 5π/3, 7π/4, 2π

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Arrange the angles in increasing order of their cosines. 3pi/4, pi, 7pi/6, 5pi/3, 7pi-example-1
User Joa Ebert
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