Calculus question using e?
height of a tree =
h(t) = (140)/(1+210e^-0.24t)
t is the age of the tree in years
estimate the age of a 70 foot tree
height of a tree =
h(t) = (140)/(1+210e^-0.24t)
t is the age of the tree in years
estimate the age of a 70 foot tree
DWRead
You are missing a set of parentheses.
h(t) = 140/(1+210e^(-0.24t))
70 = 140/(1+210e^(-0.24t))
1+210e^(-0.24t) = 140/70 = 2
210e^(-0.24t) = 1
e^(-0.24t) = 1/210
-0.24t = ln(1/210)
t = ln(1/210)/(-0.24) ≅ 22.3 years
cidyah
h(t) = (140)/(1+210e^-0.24t)
70 = 140 / (1+ 210 e^(-0.24t) )
70 ( 1+ 210 e^(-0.24t) ) = 140
70 + (210)(70) e^(-0.24t) = 140
(210)(70) e^(-0.24t) = 140-70
14700 e^(-0.24t) = 70
e^(-0.24t) = 70/14700
-0.24t = ln (70/14700)
t = - ln(70/14700) / 0.24
t = 22.28 years (age of tree)
Bryce
70=140/[1+210e^(-0.24t)]
1+210e^(-0.24t)=2
e^(-0.24t)=1/210
-0.24t=ln(1/210)
t≈22.3 years old