Дано: 3sina - 3cosa = 1Найдите: sina*cosa

[latex]3sin a - 3 cos a=1[/latex] [latex]3(sina-cos a)=1[/latex] [latex]sina-cos a=\frac{1}{3}[/latex] [latex](sina-cos a)^2=(\frac{1}{3})^2[/latex] [latex]sin^2-2sinacos a+cos^2a=\frac{1}{9}[/latex] [latex]1-2sin a cos a=\frac{1}{9}[/latex] [latex]2sin a cos a=1-\frac{1}{9}[/latex] [latex]2sin a cos a=\frac{8}{9}[/latex] [latex]sin a cos a=\frac{8}{9}:2[/latex] [latex]sin a cos a=\frac{4}{9}[/latex]