SAT II Math I : SAT Subject Test in Math I

Study concepts, example questions & explanations for SAT II Math I

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Example Questions

Example Question #2 : Graphing Polynomial Functions

Which of the graphs best represents the following function?

Possible Answers:

None of these

Graph_exponential_

Graph_line_

Graph_parabola_

Graph_cube_

Correct answer:

Graph_parabola_

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_

Example Question #5 : Graphing Polynomial Functions

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

Possible Answers:

Incorrect 1

Incorrect 3

Incorrect 2

Cannot be determined

Correct answer

Correct answer:

Correct answer

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

Example Question #2 : Graphing Other Functions

Define a function .

 for exactly one real value of  on the interval .

Which of the following statements is correct about ?

Possible Answers:

Correct answer:

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 .

Example Question #1 : Solving Functions From Word Problems

At Joe's pizzeria a pizza costs $5 with the first topping, and then an additional 75 cents for each additional topping.

If  represents the number of toppings on a pizza, what function represents the cost of a pizza with at least one topping?

Possible Answers:

Correct answer:

Explanation:

Notice that the question describes a linear equation because there is a constant rate of change (the cost per topping). This means we can use slope intercept form to describe the scenario. 

Recall that slope intercept form is

The value of  is the -value when . In this case  means there are zero additional toppings and the question tells us that this pizza costs $5 so:

 is the slope, or rate of change as  increases. In this case each additional topping costs  cents. Notice that the units have shifted from dollars to cents so we must write this as

Notice that the first topping is included in the $5 cost. The  cent charge only applies to additional toppings. So one less than the number of toppings is equivalent to:

Putting all these steps together we get:

Example Question #1 : 2 Dimensional Geometry

Swimming_pool

The above figure depicts the rectangular swimming pool at an apartment. The apartment manager needs to purchase a tarp that will cover this pool completely. However, because of the cutting device the pool store uses, the length and the width of the tarp must each be a multiple of three yards. Also, the tarp must be at least one yard longer and one yard wider than the pool.

What will be the minimum area of the tarp the manager purchases?

Possible Answers:

Correct answer:

Explanation:

Three feet make a yard, so the length and width of the pool are  yards and  yards, respectively. Since the dimensions of the tarp must exceed those of the pool by at least one yard, the tarp must be at least  yards by  yards; but since both dimensions must be multiples of three yards, we take the next multiple of three for each.

The tarp must be 18 yards by 15 yards, so the area of the tarp is the product of these dimensions, or

 square yards.

Example Question #2 : 2 Dimensional Geometry

Triangle

Note: Figure NOT drawn to scale.

Refer to the figure above, which shows a square inscribed inside a large triangle. What percent of the entire triangle has been shaded blue?

Possible Answers:

Insufficient information is given to answer the question.

Correct answer:

Explanation:

The shaded portion of the entire triangle is similar to the entire large triangle by the Angle-Angle postulate, so sides are in proportion. The short leg of the blue triangle has length 20; that of the large triangle, 30. Therefore, the similarity ratio is . The ratio of the areas is the square of this, or , or 

The blue triangle is therefore  of the entire triangle, or  of it.

Example Question #3 : 2 Dimensional Geometry

Right_triangle

Note: Figure NOT drawn to scale.

Refer to the above diagram. What is the area of ?

Possible Answers:

Insufficient information is given to answer the problem.

Correct answer:

Explanation:

If we see hypotenuse  as the base of the large triangle, then we can look at the segment perpendicular to it, , as its altitude. Therefore, the area of  is

.

, as the length of the altitude corresponding to the hypotenuse, is the geometric mean of the lengths of the parts of the hypotenuse it forms; that is, the square root of the product of the two:

The area of  is therefore

Example Question #4 : 2 Dimensional Geometry

Swimming_pool

The above figure depicts the rectangular swimming pool at an apartment. The apartment manager needs to purchase a tarp that will cover this pool completely, but the store will only sell the material in multiples of ten square yards. How many square yards will the manager need to buy?

Possible Answers:

Correct answer:

Explanation:

Three feet make a yard, so the length and width of the pool are  yards and  yards; the area of the pool, and that of the tarp needed to cover it, must be the product of these dimensions, or

 square yards. 

The manager will need to buy a number of square yards of tarp equal to the next highest multiple of ten, which is 200 square yards.

Example Question #1 : Geometry

Right_triangle

Note: Figure NOT drawn to scale.

Refer to the above diagram. In terms of area,  is what fraction of ?

Possible Answers:

Insufficient information is given to answer this question.

Correct answer:

Explanation:

The area of , being right, is half the products of its legs, which is:

 

The area of  is one half the product of its base and height; we can use its hypotenuse  as the base and  as the height, so this area is

 

Therefore, in terms of area,  is  of .

Example Question #1 : Geometry

Right_triangle

Note: Figure NOT drawn to scale.

Refer to the above diagram. Give the ratio of the area of  to that of .

Possible Answers:

Insufficient information is given to answer the question.

Correct answer:

Explanation:

, as the length of the altitude corresponding to the hypotenuse, is the geometric mean of the lengths of the parts of the hypotenuse it forms; that is, it is the square root of the product of the two:

.

The areas of  and , each being right, are half the products of their legs, so:

The area of  is 

The area of  is 

The ratio of the areas is  - that is, 4 to 1.

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