[MOVED] Exponential Fcns: Demand for lumber is increasing at

[RCook]

I need help in getting started on this. I am drawing a blank. The word problem:

World demand D (in billions of cubic feet) for timber is increasing at a rate of 1.8% each year. In 1981 the demand was 46.6 billion cubic feet of timber.

a) Explain why D is an exponential function of years t since 1981.

b) Find a formula expressing D as an exponential function of t.

c) What is the decade percentage growth?

d) After how many years will the demand for timber be 93.4 billion cubic feet?

I have a TI-83 calculator. I don't understand the concept of exponential functions. I understand linear and power functions, but not this one. I can't figure out how to use the word problem to solve this. Any help is appreciated. Thank you in advance.

 

[skeeter]

World demand D (in billions of cubic feet) for timber is increasing at a rate of 1.8% each year. In 1981 the demand was 46.6 billion cubic feet of timber

\(\displaystyle D = D_0(1.018)^t\)

where D₀ is the initial demand at some time you call t = 0, and t is the time in years.

for your problem, let D₀ = demand in 1981 ... 46.6 billion ft³

\(\displaystyle D = 46.6(1.018)^t\)

can you proceed from here?

 

[RCook]

Yes, thank you.