Question

30/(sin^2 26º + sin^2 146º + sin^2 94º) 

Answer 1

                                       Решение:

Смотри вложение:.....

Answer 2

30/(sin^2 26º + sin^2 146º + sin^2 94º)  =30/((1-cos52)/2+(1+cos112)/2+(1+cos8)/2)=
=30(3/2+(cos8+cos112-cos52)/2)=30/(3/2+(cos8-2sin30sin82)/2)=
=30/(3/2+(cos8-sin82)/2)=30/(3/2)=20