(cos64°cos4°+ cos86°cos26°)/(cos71°cos41° + cos49°cos19° - вопрос №64486267141491915767084 от Mirskaya 10.08.2021 15:41

Question

Математика: (cos64°cos4°+ cos86°cos26°)/(cos71°cos41° + cos49°cos19° ) = -1

Mirskaya · Answer

(сos(90-26)*cos4+cos(90-4)*cos26)/(cos(90-19)*cos41+cos(60-41)*cos19)==(sin26cos4+sin4*cos26)/(sin19*cos41+sin41cos19)==sin(26+4)/sin(19+41)=sin30:sin60=1/2:√3/2=1/√3...