Graphing Other Functions

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SAT Math › Graphing Other Functions

Questions 1 - 7
1

Which of the graphs best represents the following function?

Graph_parabola_

Graph_cube_

Graph_exponential_

None of these

Graph_line_

Explanation

The highest exponent of the variable term is two (). This tells that this function is quadratic, meaning that it is a parabola.

The graph below will be the answer, as it shows a parabolic curve.

Graph_parabola_

2

Screen_shot_2014-12-24_at_2.27.32_pm

Which of the following is an equation for the above parabola?

Explanation

The zeros of the parabola are at and , so when placed into the formula

,

each of their signs is reversed to end up with the correct sign in the answer. The coefficient can be found by plugging in any easily-identifiable, non-zero point to the above formula. For example, we can plug in which gives

3

Which of the following is a graph for the following equation:

Correct answer

Incorrect 1

Incorrect 3

Incorrect 2

Cannot be determined

Explanation

The way to figure out this problem is by understanding behavior of polynomials.

The sign that occurs before the is positive and therefore it is understood that the function will open upwards. the "8" on the function is an even number which means that the function is going to be u-shaped. The only answer choice that fits both these criteria is:

Correct answer

4

Simplify the following expression:

Explanation

To simplify, we must first simplify the absolute values.

Now, combine like terms:

5

Define a function .

for exactly one real value of on the interval .

Which of the following statements is correct about ?

Explanation

Define . Then, if , it follows that .

By the Intermediate Value Theorem (IVT), if is a continuous function, and and are of unlike sign, then for some . As a polynomial, is a continuous function, so the IVT applies here.

Evaluate for each of the following values:

Only in the case of does it hold that assumes a different sign at both endpoints - . By the IVT, , and , for some .

6

Where does cross the axis?

7

-7

5

-3

3

Explanation

crosses the axis when equals 0. So, substitute in 0 for :

7

Which equation best represents the following graph?

Graph6

None of these

Explanation

We have the following answer choices.

The first equation is a cubic function, which produces a function similar to the graph. The second equation is quadratic and thus, a parabola. The graph does not look like a prabola, so the 2nd equation will be incorrect. The third equation describes a line, but the graph is not linear; the third equation is incorrect. The fourth equation is incorrect because it is an exponential, and the graph is not an exponential. So that leaves the first equation as the best possible choice.

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