All Advanced Geometry Resources
Example Questions
Example Question #71 : Graphing
Let  be the point of intersection of the graphs of these two equations:
Evaluate .
The system has no solution.
Substitute  andÂ
 forÂ
 andÂ
, respectively, and solve the resulting system of linear equations:
Multiply the first equation by 2, and the second by 3, on both sides, then add:
      Â
Back-solve:
We need to find both  andÂ
 to ensure a solution exists. By substituting back:
and
We check this solution in both equations:
 - true.
Â
 - true.
Â
 is the solution, andÂ
, the correct choice.
Â
Â
Example Question #72 : Graphing
The graph of function  has vertical asymptoteÂ
. Which of the following could give a definition ofÂ
 ?
Given the function , the vertical asymptote can be found by observing that a logarithm cannot be taken of a number that is not positive. Therefore, it must hold thatÂ
, or, equivalently,Â
 and that the graph ofÂ
 will never cross the vertical lineÂ
. That makesÂ
 the vertical asymptote, so it follows that the graph with vertical asymptoteÂ
 will haveÂ
 in theÂ
 position. The only choice that meets this criterion is
Example Question #73 : Graphing
The graph of a function  hasÂ
-interceptÂ
. Which of the following could be the definition ofÂ
 ?
All of the other choices are correct.
All of the other choices are correct.
All of the functions are of the form . To find theÂ
-intercept of such a function, we can setÂ
 and solve forÂ
:
Since we are looking for a function whose graph has -intercept
, the equation here becomesÂ
, and we can examine each of the functions by finding the value ofÂ
.
:
Â
Â
:Â
Â
:Â
Â
:Â
Â
All four choices fit the criterion.
Example Question #74 : Graphing
The graph of a function  hasÂ
-interceptÂ
. Which of the following could be the definition ofÂ
 ?
All of the functions take the formÂ
for some integer . To find the choice that hasÂ
-interceptÂ
, setÂ
 andÂ
, and solve forÂ
:
In exponential form:
The correct choice is .
Example Question #221 : Coordinate Geometry
Define a function  as follows:
Give the -intercept of the graph ofÂ
.
Set  and evaluateÂ
 to find theÂ
-coordinate of theÂ
-intercept.
Rewrite in exponential form:
.
The -intercept isÂ
.
Example Question #11 : Graphing A Logarithm
Define functions  andÂ
 as follows:
Give the -coordinate of a point at which the graphs of the functions intersect.
The graphs of  andÂ
 do not intersect.
The graphs of  andÂ
 do not intersect.
Since , the definition ofÂ
 can be rewritten as follows:
Since , the definition ofÂ
 can be rewritten as follows:
First, we need to find the -coordinate of the point at which the graphs ofÂ
 andÂ
 meet by settingÂ
Since the common logarithms of the two polynomials are equal, we can set the polynomials themselves equal, then solve:
However, if we evaluate , the expression becomes
,
which is undefined, since a negative number cannot have a logarithm.
Consequently, the two graphs do not intersect.
Â
Example Question #81 : Graphing
The graph of a function  hasÂ
-interceptÂ
. Which of the following could be the definition ofÂ
 ?
None of the other responses gives a correct answer.
All of the functions are of the form . To find theÂ
-intercept of a function
,  we can setÂ
 and solve forÂ
:
.
Since we are looking for a function whose graph has -intercept
, the equation here becomesÂ
, and we can examine each of the functions by finding the value ofÂ
 and seeing which case yields this result.
Â
:
Â
:
Â
:
Â
:
The graph of  hasÂ
-interceptÂ
 and is the correct choice.
Example Question #223 : Coordinate Geometry
Define a function  as follows:
A line passes through the - andÂ
-intercepts of the graph ofÂ
. Give the equation of the line.
The -intercept of the graph ofÂ
 can befound by settingÂ
 and solving forÂ
:
Rewritten in exponential form:
The -intercept of the graph ofÂ
 isÂ
.
Â
The -intercept of the graph ofÂ
 can be found by evaluatingÂ
The -intercept of the graph ofÂ
 isÂ
.
Â
If  andÂ
are theÂ
- andÂ
-intercepts, respectively, of a line, the slope of the line isÂ
. SubstitutingÂ
 andÂ
, this is
.
Setting  andÂ
 in the slope-intercept form of the equation of a line:
Example Question #224 : Coordinate Geometry
Define functions  andÂ
 as follows:
Give the -coordinate of a point at which the graphs of the functions intersect.
The graphs of  andÂ
 do not intersect.
Since , the definition ofÂ
 can be rewritten as follows:
 .Â
Find the -coordinate of the point at which the graphs ofÂ
 andÂ
 meet by settingÂ
Since the common logarithms of the two polynomials are equal, we can set the polynomials themselves equal, then solve:
The quadradic trinomial can be "reverse-FOILed" by noting that 2 and 6 have  product 12 and sum 8:
Either , in which caseÂ
or
, in which caseÂ
Note, however, that we can eliminate  as a possibleÂ
-value, since
,
an undefined quantity since negative numbers do not have logarithms.Â
SinceÂ
andÂ
,
 is the correctÂ
-value, andÂ
 is the correctÂ
-value.
Example Question #11 : Graphing
This graph shows the graph of . The blue point has an
-coordinate of
. What is the
-coordinate?
This point has an x-coordinate of 8, so we can figure out what y is just by plugging in 8 for x:
This can be evaluated using a calculator, or just by understanding what a logarithm means.
This is essentially asking "2 to what power gives us 8," which is 3.
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