Question

已知cosθ-根号5sinθ=根号6sin（φ-θ),求tanφ

Answer 1

asin α+bcos α=√(a^2+b^2)sin(α+φ),其中tan φ=b/a

cosθ-根号5sinθ=根号5sin(-θ)+cos(-θ)=根号6sin（φ-θ)=√6sin(atan(1/√5)-θ)

tan φ=1/√5