Use the Formula $a \sin B \theta + b \cos B \theta = \sqrt { a ^ { 2 } + b ^ { 2 } } \cos ( B \theta - C )$

Multiple Choice

Use the formula $a \sin B \theta + b \cos B \theta = \sqrt { a ^ { 2 } + b ^ { 2 } } \cos ( B \theta - C )$ , where $C = \arctan ( a / b ) , a = 3 , b = 7 , B = 2$ to rewrite the trigonometric expression in the following form.
$y = \sqrt { a ^ { 2 } + b ^ { 2 } } \cos ( B \theta - C )$ $a \sin B \theta + b \cos B \theta$

A) $\sqrt { 58 }$ $\cos ( 2 \theta + 0.4049 )$
B) $\sqrt { 58 }$ $\cos ( 2 \theta - 0.4049 )$
C) 7 $\cos ( 2 \theta - 0.4049 )$
D) 3 $\cos ( 2 \theta - 0.4049 )$
E) 3 $\cos ( 2 \theta + 0.4049 )$