SOLUTION: Find the solutions of the equation that are in the interval [0, 2π). (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)
cos u ͨ
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-> SOLUTION: Find the solutions of the equation that are in the interval [0, 2π). (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)
cos u ͨ
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Question 600086: Find the solutions of the equation that are in the interval [0, 2π). (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)
cos u − cos 2u = 0 Answer by htmentor(1343) (Show Source):
You can put this solution on YOUR website! Since cos(2u) = 2*cos^2(u) - 1, we can write the equation as
cos(u) - (2*cos^2(u) - 1) = 0
2*cos^2(u) - cos(u) - 1 = 0
Factor:
(2*cos(u)+1)(cos(u)-1) = 0
This gives cos(u) = -1/2 and cos(u) = 1
On the interval 0 <= u < 2, the solutions are u = 0, and
