Answer: a) height after t years be [tex]h(t)=0.8t^2+3t+13[/tex]
b) 73.2 cm
Step-by-step explanation:
Since we have given that
[tex]\dfrac{dh}{dt}=1.6t+3\\\\\int\limits {dh} =\int\limits {1.6t+3} \, dx \\\\h(t)=0.8t^2+3t+C[/tex]
Since the seedlings are 13 cm tall.
so, height after t years would be
[tex]h(t)=0.8t^2+3t+13[/tex]
(b) How tall are the shrubs when they are sold?
After 7 years of growth, the height of shrubs would be
[tex]h(7)=0.8(7)^2+3\times 7+13\\\\h(7)=73.2\ cm[/tex]
Hence, a) height after t years be [tex]h(t)=0.8t^2+3t+13[/tex]
b) 73.2 cm