Algebra II : Functions and Graphs

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #52 : Polynomial Functions

Try without a calculator.

The graph of a function with the given equation forms a parabola that is characterized by which of the following?

Possible Answers:

None of these

Concave to the left

Concave to the right

Concave downward

Concave upward

Correct answer:

Concave to the left

Explanation:

The graph of an equation of the form

is a horizontal parabola. Whether it is concave to the left or to the right depends on the sign of . Since , a negative number, the parabola is concave to the left.

Example Question #602 : Functions And Graphs

How many -intercepts does the graph of the following function have?

Possible Answers:

Five

Zero

Ten

Two

One 

Correct answer:

One 

Explanation:

The graph of a quadratic function  has an -intercept at any point  at which , so, first, set the quadratic expression equal to 0:

The number of -intercepts of the graph is equal to the number of real zeroes of the above equation, which can be determined by evaluating the discriminant of the equation, . Set , and evaluate:

The discriminant is equal to zero, so the quadratic equation has one real zero, and the graph of  has exactly one -intercept.

Example Question #603 : Functions And Graphs

The vertex of the graph of the function 

appears in __________.

Possible Answers:

None of these

Quadrant I

Quadrant IV

Quadrant II

Quadrant III

Correct answer:

Quadrant I

Explanation:

The graph of the quadratic function  is a parabola with its vertex at the point with coordinates

.

Set ; the -coordinate is 

.

Evaluate  by substitution:

The vertex has a positive -coordinate and a positive -coordinate, putting it in the upper right quadrant, or Quadrant I.

Example Question #51 : Polynomial Functions

The vertex of the graph of the function 

appears in __________.

Possible Answers:

None of these

Quadrant IV

Quadrant III

Quadrant II

Quadrant I

Correct answer:

Quadrant III

Explanation:

The graph of the quadratic function  is a parabola with its vertex at the point with coordinates

.

Set ; the -coordinate is .

Evaluate  by substitution:

The vertex has a negative -coordinate and a negative -coordinate, putting it in the lower left quadrant, or Quadrant III.

Example Question #1 : Transformations Of Polynomial Functions

What transformations have been enacted upon when compared to its parent function, ?

Possible Answers:

vertical stretch by a factor of 4

horizontal stretch by a factor of 2

horizontal translation 6 units right

vertical stretch by a factor of 4

horizontal compression by a factor of 2

horizontal translation 6 units right

vertical stretch by a factor of 4

horizontal stretch by a factor of 2

horizontal translation 3 units right

vertical stretch by a factor of 4

horizontal compression by a factor of 2

horizontal translation 3 units right

Correct answer:

vertical stretch by a factor of 4

horizontal compression by a factor of 2

horizontal translation 3 units right

Explanation:

First, we need to get this function into a more standard form.

Now we can see that while the function is being horizontally compressed by a factor of 2, it's being translated 3 units to the right, not 6. (It's also being vertically stretched by a factor of 4, of course.)

Example Question #1 : Transformations Of Polynomial Functions

Define  and  .

Find .

Possible Answers:

Correct answer:

Explanation:

By definition, , so

Example Question #2 : Transformations Of Polynomial Functions

Define  and .

Find .

Possible Answers:

Correct answer:

Explanation:

By definition, , so

Example Question #3 : Transformations Of Polynomial Functions

Write the transformation of the given function moved five units to the left:

Possible Answers:

Correct answer:

Explanation:

To transform the function horizontally, we must make an addition or subtraction to the input, x. Because we are asked to move the function to the left, we must add the number of units we are moving. This is the opposite of what one would expect, but if we are inputting values that are to the left of the original, they are less than what would have originally been. So, to counterbalance this, we add the units of the transformation.

For our function being transformed five units to the left, we get

 

Example Question #601 : Functions And Graphs

Write the transformation of the given function flipped, and moved one unit to the left:

Possible Answers:

Correct answer:

Explanation:

To transform a function horizontally, we must add or subtract the units we transform to x directly. To move left, we add units to x, which is opposite what one thinks should happen, but keep in mind that to move left is to be more negative. To flip a function, the entire function changes in sign.

After making both of these changes, we get

Example Question #6 : Transformations Of Polynomial Functions

Transform the function by moving it two units up, and five units to the left:

Possible Answers:

Correct answer:

Explanation:

To transform a function we use the following formula,

where h represents the horizontal shift and v represents the vertical shift.

In this particular case we want to shift to the left five units,

and vertically up two units,

.

Therefore, the transformed function becomes,

.

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