question_answer

Let\[f(x)=cos\text{ }x\text{ (sin}\,\text{x+}\sqrt{{{\sin }^{2}}x+{{\sin }^{2}}}\theta \text{)}\], where \[\theta \] is a given constant, then maximum value of f(x) is __.

A)  \[\sqrt{1+{{\cos }^{2}}\theta }\]         

B)  \[\sqrt{1+{{\sin }^{2}}\theta }\]

C)  \[|cos\theta |\] 

D)  \[|sin\theta |\]