α∈(0,π/2)α+π/6∈(π/6,2π/3)cos(α+π/6)=4/5>0∴α+π/6∈(π/6,π/2)∴2α+π/3∈(π/3,π)cos(2α+π/3)=2cos²(α+π/6)-1=2*(4/5)²-1=32/25-1=7/25>0∴2α+π/3∈(π/3,π/2)sin(2α+π/3)=24/...