Question 1155174
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{{{tan(11pi/12)}}} = -{{{tan(pi/12)}}} = -tan(15°) = -(2 - {{{sqrt(3)}}}) = {{{sqrt(3)-2}}} = -0.26795  (approximately).   <U>ANSWER</U>
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See the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/Trigonometry-basics/Trigonometric-functions-of-half-argument-Examples.lesson>Trigonometric functions of half argument - Examples</A>, &nbsp;&nbsp;Example &nbsp;2

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