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Sloan [31]
3 years ago
7

If cos x cos (pi/7)+sin x sin(pi/7)=-(sqrt 2)/2,then x can equal

Mathematics
1 answer:
Alex17521 [72]3 years ago
3 0
Main formula cos (a - b) =cosacosb + sina sinb
arccos(-x) = pi -arccosx

<span>cos x cos (pi/7)+sin x sin(pi/7) = cos(x-pi/7)

so </span>cos(x-pi/7) = -(sqrt 2)/2,  x -pi/7 = arc cos[-(sqrt 2)/2 ]= pi - arc cos[(sqrt 2)/2<span> ]

</span>arc cos[(sqrt 2)/2 ] = Pi/4 + 2kpi, and then x -pi/7 = pi - pi/4 +2kpi,
 implies x= -pi/7 + pi - pi/4 = -<span>pi/7 + 3pi/4 = -19pi/28 + 2kpi</span>
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Step-by-step explanation:

You follow the equation (N-2)*180, then divide the answer with the the number of sides. Example for Triangle: (N-2)*180=(3-2)*180=(1)*180=180 then divide by 3 because in a triangle there are 3 sides. 180/3=60.

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Hey Guys! I need some help. This is the question... Sara travels often for her job. The miles she traveled for the last seven wo
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Using the median concept, it is found that the interquartile range of Sara's daily miles is of 21 miles.

<h3>What are the median and the quartiles of a data-set?</h3>

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  • The first quartile is the median of the first half of the data-set.
  • The third quartile is the median of the second half of the data-set.
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The ordered data-set is given as follows:

65, 72, 86, 88, 91, 93, 97

There are 7 elements, hence the median is the 4th element, of 88. Then:

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Since the quartiles are the medians of each half, the have that:

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More can be learned about the median of a data-set at brainly.com/question/3876456

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