Ответ:
Объяснение:
sin(2α)=2*sinα*cosα sinα=4/5 α∈[0;π].
cosα=√(1-sin²α)=√(1-(4/5)²)=√(1-(16/25))=√(9/25)=±(3/5)
1. α∈[0;π2] ⇒ cosα=3/5
sin(2α)=2*(4/5)*(3/5)=24/25.
2. α∈[π2;π] ⇒ cosα=-3/5
sin(2α)=2*(4/5)*(-3/5)=-24/25.
Ответ: sin(2α)=±24/25.
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Ответ:
Объяснение:
sin(2α)=2*sinα*cosα sinα=4/5 α∈[0;π].
cosα=√(1-sin²α)=√(1-(4/5)²)=√(1-(16/25))=√(9/25)=±(3/5)
1. α∈[0;π2] ⇒ cosα=3/5
sin(2α)=2*(4/5)*(3/5)=24/25.
2. α∈[π2;π] ⇒ cosα=-3/5
sin(2α)=2*(4/5)*(-3/5)=-24/25.
Ответ: sin(2α)=±24/25.