Concept:The expression asinx+bcosx can be written as a single sine function using the auxiliary angle method.Explanation:Rewrite the function as f(x)=asinx+bcosx.Let r=a2+b2 and choose an angle θ such that cosθ=ra and sinθ=rb.Substitute these into f(x):f(x)=r(cosθsinx+sinθcosx)f(x)=rsin(x+θ).Since −1≤sin(x+θ)≤1, the maximum value of rsin(x+θ) is r.Thus, the maximum value is a2+b2.Answer:Option A: a2+b2