Rút gọn biểu thức: $B = {\sin ^2}32^\circ - \frac{{2022.\tan 51^\circ }}{{\cot 39^\circ }} + {\sin ^2}58^\circ$.

$B = {\sin ^2}32^\circ - \frac{{2022.\tan 51^\circ }}{{\cot 39^\circ }} + {\sin ^2}58^\circ$

$B = {\sin ^2}32^\circ - \frac{{2022.\tan 51^\circ }}{{\tan 51^\circ }} + {\cos ^2}32^\circ$

$B = \left( {{{\sin }^2}32^\circ + {{\cos }^2}32^\circ } \right) - 2022$

B = 1 – 2022

B = –2021.