Question

cosa=1/2, найдите cos2a,sin2a,tga,tga/2

Answer 1

$cosa=1/2; a=60$
$cos2a=cos120=-1/2$
$sin2a=sin120= sqrt{3} /2$
$tga=tg60= sqrt{3}$
$tga/2=tg30= sqrt{3} /3$