How solve this trigo system ?

[Gerson W. Barbosa]

(09-22-2017 07:27 AM)ggauny@live.fr Wrote:  Thanks at all for your explainations. In attachement is the solution
received from teacher.

“Impossible to go further”. Not impossible at all, perhaps only more difficult to do it by hand that way.

Another way, starting from the second try, not very different from what has been suggested so far.