Question

The cost, in dollars, to produce 1 watt of solar energy is a function of the number of years

Answer 1

Answer:

In the figure attached, the graph of the function is shown.

1. f(9) ≈ 6 means that at t = 9 (year 1977 + 9 = 1986) the cost to produce 1 watt of solar energy was $6

2. f(4) ≈ 25, which means at year 1981 (=1977 + 4) the cost was $25 per watt  

f(3.5) ≈ 28, which means at half of year 1980 (=1977 + 3.5) the cost was $28 per watt  

3. When f(t) = 45, t is equal to 2, which means that the year wass 1979 (= 1977 + 2)

4. From the graph we can compute the following table:

x  |  y

0  |  80

1   |  60

The general exponential decay formula is:

f(x) = a*b^x

where a is the initial value and b si the decay factor. Replacing with data from the table:

f(0) = a*b^0

80  = a

f(1) = a*b^1

60/80 = b

0.75 = b