SOLUTION: Please solve the following equation. (Enter your answers as a comma-separated list. Let k be any integer. Enter DNE is there is no solution.) 2 cos 2θ − 1 = 0 (a) Fi

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Question 924330: Please solve the following equation.
(Enter your answers as a comma-separated list. Let k be any integer. Enter DNE is there is no solution.)
2 cos 2θ − 1 = 0
(a) Find all solutions of the equation.
θ =
(b) Find the solutions in the interval [0, 2π).
θ =

Thanks

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Part a)


Solve for














or where k is any integer.


or


or


The general solutions are or where k is any integer.


You can condense that into one equation: (take note of the plus/minus)


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Part b)


We'll find the first set of solutions.


Plug in integer values of k into to generate solutions. Make sure you are between and roughly.


Plug in














This is in the interval [0,2pi), so we keep it.


---------------------------------


Plug in

















This is in the interval [0,2pi), so we keep it.


---------------------------------


Plug in











we have gone over 6.28, so we stop here and we don't include this solution because it is not in the interval [0,2pi)


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Now we move onto the second part.


Plug in integer values of k into to generate solutions. Make sure you are between and roughly.


Plug in











That is less than x = 0, so we toss out this solution.


---------------------------------


Plug in

















This is in the interval [0,2pi), so we keep it.


---------------------------------


Plug in

















This is in the interval [0,2pi), so we keep it.


---------------------------------


Plug in











we have gone over 6.28, so we stop here and we don't include this solution because it is not in the interval [0,2pi)


---------------------------------


The exact solutions to part b) are , , , . They are exact solutions in terms of


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Let me know if that helps or not. Thanks.

If you need more help, feel free to email me at jim_thompson5910@hotmail.com

My Website: http://www.freewebs.com/jimthompson5910/home.html

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