The number of research articles in Physics Review that were written by researchers in the U.S. from 1983 through 1996 can be approximated by $A ( t ) = - 0.01 t ^ { 2 } + 0.24 t + 3.4$ billion dollars (t is time in years since 1983).
Find an appropriate domain of A.

A) $[ 0,13 ]$
B) $[ 1983 , + \infty ]$
C) $[ - \infty , 13 ]$
D) $[ - \infty , 0 ]$
E) $[ 1983,1996 ]$

Question

The number of research articles in Physics Review that were written by researchers in the U.S. from 1983 through 1996 can be approximated by $A ( t ) = - 0.01 t ^ { 2 } + 0.24 t + 3.4$ billion dollars (t is time in years since 1983). 
Find an appropriate domain of A.

A) $[ 0,13 ]$
B) $[ 1983 , + \infty ]$
C) $[ - \infty , 13 ]$
D) $[ - \infty , 0 ]$
E) $[ 1983,1996 ]$

Quizplus · Accepted Answer

The domain of $A(t)$ is from 0 to 13 because $t$ represents the years since 1983, so $t=0$ corresponds to the year 1983 and $t=13$ corresponds to the year 1996.

The Number of Research Articles in Physics Review That Were A(t)=−0.01t2+0.24t+3.4A ( t ) = - 0.01 t ^ { 2 } + 0.24 t + 3.4A(t)=−0.01t2+0.24t+3.4

The Number of Research Articles in Physics Review That Were $A ( t ) = - 0.01 t ^ { 2 } + 0.24 t + 3.4$