The value of sin 120.?

1 Answer
Mar 14, 2018

#\frac{\sqrt{3}}{2}#

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Explanation:

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Use the following trigonometric identity to rewrite the given angle #\ \ \ \sin (x)=\cos (90^{\circ }-x)\ \ \ # as:

#\sin (120^{\circ })=\cos (90^{\circ }-120^{\circ })#

#=\cos (-30^{\circ })#

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Keep remember that, #\ \ cos\ \ # is an even function such that #\ \ \cos (-x)=\cos (x)\ \ #

#\cos (-30^{\circ })=\cos (30^{\circ })#

#=\frac{\sqrt{3}}{2}#

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That's it!