Question

Write a function to describe each investment of $1000:
-stock increasing in value 19% per year
-stock decreasing in value 9% each year
If the time is needed to write the function it is 3 years.
Stock increasing
$1000 * 1.19 ^ 3 = $1685.159
Stock decreasing
$1000 * 0.91 ^ 3 = $753.571
You can replace 3 by n for number of years in both cases

Did I do the math right for this, particularly the decimals?
Would this problem be considered a function?

Answer 1

The question that I have is to think of a function that you encounter in your everyday life. Carefully describe the inputs and corresponding outputs. Give your function a name and illustrate how you would use functional notation with your function. Describe the domain and range of your function.

I think the domain or input would be the initial investment and the range or output would be the profit or loss.

Answer 2

increase add
decrease subtract

compound interest in both cases
a = P(1 +r/n)^nt
1000*1.19^n
1000*0.91^n

agree

Answer 3

So would this example also be a function if you buy 100 shares at $20 each and sell them at $22 each, your profit is $200 [100 x ($22 - $20) = 100 x $2] minus commission costs of $19.90, or $181.10.

Answer 4

I am confused with the 1.19 and the 0.91 would 19% be 0.19 and 9% 0.09 as a decimal?