The formula
a(n) = 2 - 5(n-1)
is in the form
a(n) = a1 + d(n-1)
where
a1 = first term = 2
d = -5 = common difference
The first term is carried over to the recursive formula. We start with a1 = 2. The next term after that is found by subtracting 5 from the previous term. So
second term = (first term) - 5
third term = (second term) - 5
and so on
The recursive step would be
a(n) = a(n-1)-5
So that's why the answer is choice C

Integrating gives

To compute the integral, substitute
, so that
. Then

Since
for all
, we can drop the absolute value, so we end up with

Given that
, we have

so that

Answer:
<h3>
x = 6 ft. long shadow</h3><h3>
</h3>
Step-by-step explanation:
its a ratio and proportion:
<u> 15 ft. tall giraffe </u> = <u> 5 ft. tall bird </u>
18 ft. shadow x shadow
15 (x) = 18 (5)
x = 90 / 15
x = 6 ft. long shadow