Question

Linda is studying the sale of a particular brand of cereals from the year 1993 to 2004. She writes the following function to model the sale of the cereal S(t), in million dollars, after t years:

S(t) = t2 + 5t + 52

Part A: What does the y-intercept of the graph of the function represent?

Part B: What is the reasonable domain of the graph of the function?

Part C: What is the average rate of change of the sale of the cereal from the first year to the fourth year? Show your work.

Answer 1

@math&ing001

Answer 2

For the first question I would guess it's the initial investment

Answer 3

What about for the second one. Am I supposed to find the vertex?

Answer 4

No the domain of the function is where the function is defined. We know time is positive, what do you think the domain should be ?

Answer 5

I'm honestly not sure finding domains is something I never understand

Answer 6

Can you explain how?

Answer 7

Domain is basically all the values that "t" is allowed to take on.
Usually we look out for division by zero for example. But here we just make sure that "t" is not negative, because time can't be negative !

Answer 8

so would it be all realr numbers?

Answer 9

What about negative real numbers ?

Answer 10

sorry, all real positive numbers

Answer 11

would that be right?

Answer 12

Yeah correct

Answer 13

and for the last one I just substitute number 1 and 4 into the equation and then use the slope formula?

Answer 14

Yep !

Answer 15

Great! Thanks so much!

Answer 16

Don't mention it =)