Posted by **Anonymous** on Wednesday, September 21, 2011 at 8:12pm.

A tree grows 2.80 m during the first year since it was planted. During each subsequent year the tree's growth is 85% of its growth the previous year.

a) Calculate to the nearest 0.001m, the growth of the tree in the fourth year.

Tn = ar^n-1

T4 = 2.80(0.85)^10-1

T4 = 2450

I dont get how to do this, the answer is wrong, its supposed to be 1.72m :\

Determine the first year in which the growth of the tree is less than half a metre.

- Calculus -
**Reiny**, Wednesday, September 21, 2011 at 8:27pm
Where in the world did you get 10 in the 10-1

should have been 4-1

T4 = 2.8(.85)^3 = 1.719 or 1.72

for growth to be .5

.5 = 2.8(.85)^(n-1)

divide by 2.8

.17857.. = .85^(n-1)

take log of both sides

log (.17857..) = log [.85^(n-1)]

log (.17857..) = (n-1)log [.85]

n-1 = log (.17857..) / log [.85] = 10.6

n = 11.6

in year 11, growth = 2.8(.85)^10 = .5512

in year 12, growth = 2.8(.85)^11 = .468

so what do you think?

- Calculus -
**Anonymous**, Wednesday, September 21, 2011 at 8:35pm
So that would be Year 12.

- Calculus -
**Reiny**, Wednesday, September 21, 2011 at 8:36pm
yes

## Answer this Question

## Related Questions

- Economic - All of the following refer to the Economy of Ecoland: - GDP in 1990 ...
- Economics - A nations capital goods wear out over time, so a portion of it's ...
- College Level Calculus - Each orange tree grown in California produces 720 ...
- Math - 1. The table shows the growth in the number of Mcdonalds restaurants ...
- math - carlas clothing shop opened eight years ago. the first year she made $3,...
- college algebra HELP - The population of a city was 166 thousand at the begining...
- Calc and Vectors - The owner of an orange grove estimates that 150 orange trees ...
- math - As compared to its first year of operation, ABC company grew 8% in the ...
- msu - As compared to its first year of operation, ABC company grew 8% in the ...
- Economics - Suppose consumers spent $42 million on Christmas trees last year ...

More Related Questions