Perform the Requested Operation or Operations $$f ( x ) = \sqrt { x + 6 } ; g ( x ) = \cos x$$

Multiple Choice

Perform the requested operation or operations. Find the domain of each.
- $$f ( x ) = \sqrt { x + 6 } ; g ( x ) = \cos x$$
Find $f - g$ .

A) $\sqrt { x + 6 } + \cos x$ ; domain: $[ - 6 , \infty )$
B) $\frac { \cos x } { \sqrt { x + 6 } } ;$ domain: $[ - 6 , \infty )$
C) $( \cos x ) ( \sqrt { x + 6 } )$ ; domain: $[ - 6 , \infty )$
D) $\sqrt { x + 6 } - \cos x$ ; domain: $[ - 6 , \infty )$