Let $f ( x ) = \sqrt { x }$ Which of the Following Is Equal To

Multiple Choice

Let $f ( x ) = \sqrt { x }$ Which of the following is equal to $\lim _ { x \rightarrow 4 } \frac { f ( x ) - f ( 4 ) } { x - 4 }$ ?

A) $- \frac { 1 } { 4 }$
B) $\frac { 1 } { 4 }$
C) $- \frac { 1 } { 2 }$
D) $\frac { 1 } { 2 }$
E) Does not exist