Question

sin(10°)-cos(10°)*ctg(130°)
помгите решить

Answer 1

ctg130=ctg(90+40)=-tg40=-sin40/cos40
sin10-cos10(-sin40/cos40)=(sin10cos40+cos10sin40)/cos40=
=sin(10+40)/cos40=sin50/cos40=sin(90-40)/cos40=cos40/cos40=1