Подробное решения нужен значение выражения: tg^2(15)+4tg60

Sin²15/cos²15 +4*√3=(1-cos30)/(1+cos30)  + 4√3=(1-0,5)/(1+0,5) +4√3=1/3+4√3=
=(1+12√3)/3

Tg^2 (15) + 4 tg 60=sin^2(15) / cos^(15)  + 4*sgrt3=(1- cos(2*15)) / (1 + cos(2*15)) + 4sgrt3=( 1- cos30)/ (1+ cos 30)   + 4sgrt3= (1- sgrt3/2)/ (1+sgrt3/2)  + 4sgrt3=
= (2-sgrt3) / (2+sgrt3)  + 4sgrt3 = (2-sgrt3 + 4sgrt3(2+sgrt3)) / (2+sgrt3) =
=(2- sgrt3 + 8 sgrt3 + 4*3) / (2 + sgrt3) = (14  + 7sgrt3) / (2+ sgrt3) =
=7(2+sgrt3) / (2+sgrt3) = 7