令cost=a/√(a²+b²),sint=b/√(a²+b²),
则有：asinx+bcosx = √(a²+b²){sinxcost+cosxsint} = √(a²+b²)sin(x+t)
tant = sint/cost = b/a令cost=a/√(a²+b²)，sint=b/√(a²+b²)，
则有：asinx+bcosx = √(a²+b²){sinxcost+cosxsint} = √(a²+b²)sin(x+t)
tant = sint/cost = b/a
看不清看不清啊！。。。。