d. Is your solution to part c an overestimate or underestimate of the actual number of bacteria colonies at 1:30? Justify your answer using concepts from calculus.

\( 9 y ^ { \prime \prime } - 12 y ^ { \prime } + 4 y > 0 \)

\( \sum _ { n = 1 } ^ { \infty } \frac { 1 \cdot 3 \cdot 5 \cdot \ldots \cdot ( 2 n - 1 ) } { 2 \cdot 5 \cdot 8 \cdot \ldots \cdot ( 3 n - 1 ) } \)

\( \int _ { 2 } ^ { 5 } \int _ { 0 } ^ { \pi / 2 } r \cos \theta r \sin \theta d \theta d r = \)

\( \sum _ { n = 1 } ^ { \infty } \frac { 1 \cdot 3 \cdot 5 \cdot \ldots \cdot ( 2 n - 1 ) } { 2 \cdot 5 \cdot 8 \cdot \ldots \cdot ( 3 n - 1 ) } \)

Find \( \int_{C} \bar{z} d z \), where \( C \) is a semicizcle \( |z|=1 \)