Question 1119175
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<pre>
tan(165°) = tan(120°+45°) = {{{(tan(120^o)+tan(45^o))/(1-tan(120^o)*tan(45^o))}}}


    tan(120°) = {{{-sqrt(3)}}};  tan(45°) = 1  =============>


= {{{(-sqrt(3)+1)/(1-(-sqrt(3)*1))}}} = {{{(1-sqrt(3))/(1+sqrt(3))}}} = {{{(1-sqrt(3))/(1+sqrt(3))}}} . {{{(1-sqrt(3))/(1-sqrt(3))}}} = {{{(1-2*sqrt(3)+3)/(1-3)}}} = {{{(4-2*sqrt(3))/(-2)}}} = {{{sqrt(3)-2}}}.
</pre>

Solved.