(1) √3 sinα+cosα
=2(√3/2 sinα+1/2cosα)
=2(cosπ/6sinα+sinπ/6cosα)
=2sin(α+π/6)
(2) 5sinα-12cosα
=13(5/13sinα-12/13cosα)
=13(cosφsinα-sinφcosα)
=13sin(α+φ) tanφ=12/5
由计算器求出φ=1.18.
∴原式=13sin(α+1.18).
(1) √3 sinα+cosα
=2(√3/2 sinα+1/2cosα)
=2(cosπ/6sinα+sinπ/6cosα)
=2sin(α+π/6)
(2) 5sinα-12cosα
=13(5/13sinα-12/13cosα)
=13(cosφsinα-sinφcosα)
=13sin(α+φ) tanφ=12/5
由计算器求出φ=1.18.
∴原式=13sin(α+1.18).