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Q. 6

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Precalculus Enhanced with Graphing Utilities

Found in: Page 582

Book edition 6th

Author(s) Sullivan

Pages 1200 pages

ISBN 9780321795465

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Short Answer

$\cos \frac{2 π}{3} =________.$

The value of $\cos \frac{2 π}{3} = - \frac{1}{2} .$

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Step by Step Solution

TABLE OF CONTENTS :

TABLE OF CONTENTS

Step 1. Given Information

The cosine function is a periodic function. The ratio of the adjacent side to the hypotenuse of the right-angled triangle is called the cosine function.

Step 2. Filling the blank

We can write $\cos \frac{2 π}{3}$ as $\cos (π - \frac{π}{3}) .$

As we know cosine function is negative in the second quadrant.

Thus,

$\cos \frac{2 π}{3} = \cos (π - \frac{π}{3}) \cos \frac{2 π}{3} = - \cos (\frac{π}{3}) \cos \frac{2 π}{3} = - \frac{1}{2}$

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Precalculus Enhanced with Graphing Utilities

Answers without the blur.

Short Answer

$\cos \frac{2 π}{3} =________.$

Step by Step Solution

Step 1. Given Information

Step 2. Filling the blank

Most popular questions for Math Textbooks

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Precalculus Enhanced with Graphing Utilities

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Short Answer

cos2π3=________.

Step by Step Solution

Step 1. Given Information

Step 2. Filling the blank

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$\cos \frac{2 π}{3} =________.$