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Solve for x if sin 3x = cos 3x.

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danixsaur | Student, Grade 11 | eNotes Newbie

Posted January 9, 2011 at 2:27 PM via web

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Solve for x if sin 3x = cos 3x.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted January 9, 2011 at 3:51 PM (Answer #1)

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We have to solve sin 3x = cos 3x

First divide both sides by cos 3x

=> sin 3x / cos 3x = cos 3x/ cos 3x

=> tan 3x = 1

=> 3x = arc tan 1

=> 3x = pi/4

=> x = pi/12

Also, we know that the tan function is periodic and values repeat after pi radians.

So, x = pi/12 + n*pi

Therefore x = pi/12 + n*pi.

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