Sin70 Cos40 - Sin160 Sin40=Sin70 Cos40 - Sin(90+70) Sin40=Sin70 Cos40 - cos70Sin40=sin(70-40)=sin30=1/2
Sin20 sin 80 +Sin 110 Cos 80=Sin20 sin 80 +Sin(90+20) Cos 80=
Sin20 sin 80 +cos20 Cos 80=cos(80-20)=cos60=1/2
тогда
(Sin70 Cos40 - Sin160 Sin40)/(Sin20 sin 80 +Sin 110 Cos 80)=(1/2)/(1/2)=1
Sin70 Cos40 - Sin160 Sin40=Sin70 Cos40 - Sin(90+70) Sin40=Sin70 Cos40 - cos70Sin40=sin(70-40)=sin30=1/2
Sin20 sin 80 +Sin 110 Cos 80=Sin20 sin 80 +Sin(90+20) Cos 80=
Sin20 sin 80 +cos20 Cos 80=cos(80-20)=cos60=1/2
тогда
(Sin70 Cos40 - Sin160 Sin40)/(Sin20 sin 80 +Sin 110 Cos 80)=(1/2)/(1/2)=1