Solving equation (trig.)

2008-05-24 5:11 am

What is the principal root (in radians) of...
6cos(2x) + 1 = 4

In other word, what is x...?

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回答 (3)

2008-05-24 5:28 am

✔ 最佳答案

6cos(2x)+1=4
6cos(2x)=3
cos(2x)=1/2
2x=π/3，(5π)/3，(7π)/3 or (11π)/3
x=π/6，(5π)/6，(7π)/6 or (11π)/6

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2008-05-24 5:53 am

6cos(2x) + 1 = 4
cos2x=1/2
2x=360°pi±60°
x=180°pi±30°

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2008-05-24 5:26 am

6cos(2x) + 1 = 4
6cos(2x) = 3
cos(2x) = 3/6
cos(2x) = 1/2
2x=(2/3)pi+2k*pi
x=(1/3)pi+k*pi

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