Math

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I have the answer to this question but I have no idea how to get there.

Solve for all values of x if 0¡x¡2¥ð.
cos©÷(4x)+cos(4x)=0

The answer I have is:
x=¥ð/8, 3¥ð/8, 5¥ð/8, 7¥ð/8, 9¥ð/8, 11¥ð/8, 13¥ð/8, ¥ð/4,3¥ð/4, 5¥ð/4, 7¥ð/4

  • Math -

    Sorry, it seems cutting from Word and pasting here doesn't work. again the problem is.

    Solve for all values of c if 0 is less than or equal to x, which is less than or equal to 2pie.
    (cosine squared of 4x) + (cosine of 4x)=0

    the answer is
    x= pie/8, 3pie/8, 5pie/8, 7pie/8, 9pie/8, 11pie/8, 13pie/8, 15pie/8, pie/4, 3pie/4, 5pie/4, 7pie/4

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