Find the Average Value of the Function F Over the Given

Multiple Choice

Find the average value of the function f over the given region.
- $f ( x , y ) = \sin \frac { 7 } { 2 } ( x + y )$ over the square $0 \leq x \leq \frac { \pi } { 7 } , 0 \leq y \leq \frac { \pi } { 7 }$ .

A) $4 \pi ^ { 2 }$
B) $\pi ^ { 2 }$
C) $\frac { 8 } { \pi ^ { 2 } }$
D) $\frac { 6 } { \pi ^ { 2 } }$