If f(x) = x2 + x + 1, then what is f(3)?
f(3) = 32 + 3 + 1 = 13
The above table gives the world population P at a given year t. What is P(1950)?
2,560,000,000 people
What is g(0)?
g(0) = -2
The rule that the US Postal Service used as of 2019 is as follows: the cost is 1 dollar for up to 1 oz, plus 15 cents for each additional ounce (or less) up to 13 oz.
What is the cost of sending a letter that weighs 3 oz?
$1.30
What is the area of a triangle? Let b = base and h = height.
A = (b*h)/2
What is f(x) is the following piecewise function, what is f(1.5)?
f(x) = {(x,if 0\leq x \leq 1),(2-x, if 1 < x \leq 2),(0, if x >2):}
1.5 < 2 so f(1.5) = 2 - 1.5 = 0.5
Does the following table represent a function? Why or why not?
No. A function is a rule that assigns to each input element x exactly one output element y. In the table, the input x = 5 has two different output elements y = 7 and y = 8, so this table does not represent a function.
What is g(2)?
g(2) = 1
A storage container has a total volume of 125 cm3. If we know that the storage container is in the shape of a cube, what are the dimensions of the container?
5 cm x 5 cm x 5 cm = 125 cm3
What is the equation of a line? Describe each variable.
y = mx + b, where m = slope of line, b = y-intercept (called slope-intercept form)
OR
y - y1 = m(x - x1), where m = slope of line, (x1,y1) is any point on the line (called point-slope form)
If f(x) = x3 - x and g(u) = u3 - u, is it true that f = g?
Yes, two functions are equal to one another if and only if they agree (that is, they are equal) for every input.
Give an algebraic expression to describe the function of the table below.
y = 2x + 1
Estimate what g(2.1) is.
A rectangular box has a total volume of 10 in3. The length of its base is twice its width. Let l = length of base, w = width of base, and h = height of box. Give an expression for the height of the box in terms of either l or w.
h = 10/(2w^2)in = 5/w^2 in or h = 20/l^2 in
Completely expand the following algebraic expression:
(2x + 1)(3x - 4)(x + 1)
6x^3+x^2-9x-4
If f(x) and g(x) are the following functions, is it true that f = g?
f(x) = (x^2-x)/(x-1) and g(x) = x
No. For f to be equal to g, we must have f(x) = g(x) for all inputs of x. Consider when x = 1. Then we have that g(1) = 1, however f(1) is undefined (that is, it does not exist).
f(1) = (1^2-1)/(1-1) = 0/0
The table below gives the tuition cost y of a school for a given year x. Does the table describe y as a function of x? Why or why not?
Yes, each year has exactly one tuition cost, so y is indeed a function of x.
For what values of x is f(x) greater than or equal to g(x)?
-2 \leq x \leq 2
An open-topped cylinder has a radius of 2 ft and a height of 5 ft. What is the total surface area of the open-topped cylinder?
24 \pi ft^2
If f(x) and g(x) are the following functions, what is f(g(x))?
f(x) = 1/3\sqrt{x^2 + 2x-1} + 4x and g(x) = x^2+3
f(g(x)) = 1/3 sqrt(x^4+8x^2+14)
If f(x) and g(x) are the following functions, what is f(g(4))?
f(x) = \sqrt(4x+1)/(3x^2) and g(x) = x+2
x=5/108
State the solution of the equation f(x) = -1.
The equation f(x) = -1 does not have a solution (in other words, there is no value of x such that f(x) = -1).
A rectangular box with an open top has a total volume of 10 m3. The length of its base is twice its width. Material for the base costs $10 per square meter; material for the sides cost $6 per square meter. Express the cost of materials as a function of the width of the base.
C(w) = 20w^2 + 180/w, \text{ for } w > 0
If f(x), g(x), and h(x) are the following functions, then find f(g(h(x))).
f(x) = |x^2-4|, g(x) = 2^x, h(x) = sqrt{x} + 1
f(g(h(x))) = |2^{2\sqrt{x}+2}-4|