brazil-enem 2016 Q141

brazil-enem · Other · enem__day2 Exponential Functions Applied/Contextual Exponential Modeling
Assume that a type of eucalyptus has an expected exponential growth rate in the first years after planting, modeled by the function $y(t) = a^{t-1}$, in which $y$ represents the height of the plant in meters, $t$ is considered in years, and $a$ is a constant greater than 1. The graph represents the function $y$.
Also assume that $y(0)$ gives the height of the seedling when planted, and it is desired to cut the eucalyptus when the seedlings grow 7.5 m after planting.
The time between planting and cutting, in years, is equal to
(A) 3.
(B) 4.
(C) 6.
(D) $\log_{2} 7$.
(E) $\log_{2} 15$.
Assume that a type of eucalyptus has an expected exponential growth rate in the first years after planting, modeled by the function $y(t) = a^{t-1}$, in which $y$ represents the height of the plant in meters, $t$ is considered in years, and $a$ is a constant greater than 1. The graph represents the function $y$.

Also assume that $y(0)$ gives the height of the seedling when planted, and it is desired to cut the eucalyptus when the seedlings grow 7.5 m after planting.

The time between planting and cutting, in years, is equal to

(A) 3.

(B) 4.

(C) 6.

(D) $\log_{2} 7$.

(E) $\log_{2} 15$.