All HiSET: Math Resources
Example Questions
Example Question #5 : Functions And Function Notation
Define functions and .
Give the domain of the composition .
The domain of the composition of functions is that the set of all values that fall in the domain of such that falls in the domain of .
, a polynomial function, so its domain is the set of all real numbers.
, so the domain of is the set of all values that make the radicand a nonnegative number. Since the radicand is itself, the domain of is simply the set of all nonnegative numbers, or .
Therefore, the domain of is the set of all real numbers such that
.
Equivalently,
To solve this, first, solve the corresponding equation:
Factor the polynomial at left using the difference of squares pattern:
By the Zero Factor Property, either
, in which case ,
or
, in which case .
These are the boundary values of the intervals to be tested. Choose an interior value of each interval and test it in the inequality:
Testing :
- True; include
Testing :
- False; exclude
Testing :
- True; include
Include and . Also include the boundary values, since equality is included in the inequality statement ( ).
The correct domain is .
Example Question #1 : Functions And Function Notation
Define functions and .
Give the domain of the composition .
The domain of the composition of functions is the set of all values that fall in the domain of such that falls in the domain of .
, a square root function, so the domain of is the set of all values that make the radicand a nonnegative number. Since the radicand is itself, the domain of is simply the set of all nonnegative numbers, or .
, a polynomial function; its domain is the set of all reals, so it does not restrict the domain any further.
The correct domain is .
Example Question #1 : Functions And Function Notation
Define functions and .
Give the domain of the composition .
The domain of the composition of functions is the set of all values that fall in the domain of such that falls in the domain of .
, a square root function, so the domain of is the set of all values that make the radicand a nonnegative number. Since the radicand is itself, the domain of is simply the set of all nonnegative numbers, or .
, a rational function, so its domain is the set of all numbers except those that make its denominator zero. if and only if , so from , we exclude only the value so that
;
that is,
Excluding this value from the domain, this leaves as the domain of .
Example Question #11 : Functions And Function Notation
Define functions and .
Give the domain of the function .
The domain of the sum of two functions is the intersections of the domains of the individual functions. Both and are square root functions, so their radicands must both be positive.
The domain of is the set of all values of such that:
Adding 8 to both sides:
This domain is .
The domain of is the set of all values of such that:
Subtracting 8 tfrom both sides:
This domain is
The domain of is the intersection of the domains, which is .
Example Question #4 : Domain And Range Of A Function
Define functions and
Give the domain of the composition .
None of the other choices gives the correct response.
None of the other choices gives the correct response.
The domain of the composition of functions is the set of all values that fall in the domain of such that falls in the domain of .
, a polynomial function, so the domain of is equal to the set of all real numbers, . Therefore, places no restrictions on the domain of .
, a square root function, whose domain is the set of all values of that make the radicand nonnegative. Since the radicand is itself, the domain of is simply the set of all nonnegative numbers, or . Therefore, we must select the set of all in such that , or, equivalently,
However, , so , with equality only if . Therefore, the domain of is the single-element set , which is not among the choices.
Example Question #261 : Hi Set: High School Equivalency Test: Math
Define functions and .
Give the domain of the function .
The domain of the difference of two functions is the intersections of the domains of the individual functions. Both and are square root functions, so their radicands must both be positive.
The domain of is the set of all values of such that:
Subtracting 8 tfrom both sides:
This domain is
The domain of is the set of all values of such that:
Adding to both sides:
, or
This domain is .
The domain of is the intersection of these, .
Example Question #5 : Domain And Range Of A Function
Define functions and .
Give the domain of the function .
The domain of the sum of two functions is the intersections of the domains of the individual functions.
Both and are cube root functions. There is no restriction on the value of the radicand of a cube root, so both of these functions have as their domain the set of all real numbers . It follows that also has domain .
Example Question #41 : Algebraic Concepts
Define
Give the range of the function.
The range of a function is the set of all possible values of over its domain.
Since this function is piecewise-defined, it is necessary to examine both parts of the function and extract the range of each.
For , it holds that , so
,
or
.
For , it holds that , so
,
or
The overall range of is the union of these sets, or .
Example Question #42 : Algebraic Concepts
A restaurant sets the prices of its dishes using the following function:
Price = (Cost of Ingredients) + (40% of the Cost of Ingredients) + 5
where all quantities are in U.S. Dollars.
If the cost of ingredients for a steak dish is $14, what will the restaurant set the price of the steak dish at?
$14
$19
$13.40
$19.60
$24.60
$24.60
The price of the dish is a function of a single variable, the cost of the ingredients. One way to conceptualize the problem is by thinking of it in function notation. Let be the variable representing the cost of the ingredients. Let be a function of the cost of ingredients giving the price of the dish. Then, we can turn
"Price = (Cost of Ingredients) + (40% of the Cost of Ingredients) + 5"
into a regular equation with recognizable parts. Replace "Price" with and replace "cost of ingredients" with the variable .
Simplify by combining like terms ( and ) to obtain:
The cost of ingredients for the steak dish is $14, so substitute 14 for .
All that's left is to compute the answer:
So, the steak dish will have a price of $24.60.
Example Question #2 : Functional Relationship Between Two Quantities
The plot shows the graphs of five different equations. Using shape and location, determine which graphed line corresponds to the equation .
Line E
Line A
Line C
Line B
Line D
Line B
The power of and are both 1, so this is a linear equation of order 1. Therefore, the graph must be a straight line. We can eliminate A and E, since neither are straight lines.
The equation is given in the slope-intercept form, , where stands for the slope of the line and stands for the line's y-intercept. Since , the coefficient of x, is positive here, we are looking for a line that goes upwards. We can eliminate D since it goes downwards, and therefore has a negative slope.
In the given equation, the constant , which represents the y-intercept, is also positive. Therefore, the line we are looking for also must intersect the y-axis at a positive value. The graph C appears to intersect the y-axis at a negative value, whereas the graph B appears to intersect the y-axis at a positive value. Therefore, B is the corresponding graph.