Question

Tg(21*arcsin 1/2 - 2a) = ?tga=0.5

Answer 1

$tg(21arcsin\frac{1}{2}-2a)=tg(21arcsin\frac{1}{2}-2*arctg(0.5))=\\ tg(\frac{7\pi}{2}-2arctg(0.5))=tg(2arctg0.5) = \frac{2tg(arctg0.5)}{1-tg^2(arctg0.5)} = \frac{1}{1-\frac{1}{4}}=\frac{1}{\frac{3}{4}}=\frac{4}{3}$