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Math Help - Sinus equation

  1. #1
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    Sinus equation

    Hello again.

    Im stuck again..

    How do i solve:

    sin(2y)=0.5

    should i make it in a form of

    y= sin...??

    Best Regards
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  2. #2
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    Quote Originally Posted by DenOnde View Post
    Hello again.

    Im stuck again..

    How do i solve:

    sin(2y)=0.5

    should i make it in a form of

    y= sin...??

    Best Regards
    2y = \frac{\pi}{6} + 2n \pi or 2y = \frac{5\pi}{6} + 2n \pi where n \in Z. Therefore ....
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  3. #3
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    so i should take

     y = (\pi/6)+n*\pi/2 ?

    thank you for the quick reply btw
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  4. #4
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    Quote Originally Posted by DenOnde View Post
    so i should take

     y = (\pi/6)+n*\pi/2 ?

    thank you for the quick reply btw
    No.

    You have not correctly divided by 2 both sides of the two general solutions I set up.
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  5. #5
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    But i don't really understand where the other solution come from?
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  6. #6
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    Quote Originally Posted by DenOnde View Post
    But i don't really understand where the other solution come from?
    Draw a unit circle. Then see that the sine of an angle is positive in quadrant 1 and quadrant 2.
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  7. #7
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    ah.... of course... if you have it in degrees it's equal to 180-30 therefor the second solution?

    so next i should divide both solutions by 2?

    thank you for your patience
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