Algebra II : Algebra II

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #21 : Other Factorials

Try without a calculator.

Give the value of  that makes this three-part inequality true.

Possible Answers:

The inequality has no solution.

Correct answer:

Explanation:

Given a nonnegative integer  - or  factorial - is defined to be the product of the integers from 1 to . After some exploration, multiplying 1 by 2, the result by 3, that result by 4, and so forth, we find that

Multiplying by 8, we find that

Multiplying by 9, we find that

Therefore,

Since only integers may have factorial values, it follows that the only value of  that makes the inequality true is .

Example Question #95 : Factorials

Try without a calculator:

 is equal to which expression?

Possible Answers:

None of these

Correct answer:

Explanation:

 - or  factorial - is defined to be the product of the integers from 1 to . Therefore, 

and 

,

the correct response.

Example Question #21 : Other Factorials

Try without a calculator:

Which is true about  ?

Possible Answers:

 is an undefined quantity

Cannot be determined

Correct answer:

Explanation:

 is considered to be equal to one by definition.

Example Question #97 : Factorials

Try without a calculator:

Calculate:

Possible Answers:

Cannot be determined

Correct answer:

Explanation:

 - or  factorial - is defined to be the product of the integers from 1 to . Therefore, 

Therefore, 

Since

,

it follows that 720 is the correct response. 

Example Question #1 : Natural Log

Solve for .

Possible Answers:

Correct answer:

Explanation:

The first thing we notice about this problem is that  is an exponent. This should be an immediate reminder: use logs!

The question is, which base should we choose for the log? We should use the natural log (log base e) because the right-hand side of the equation already has e as a base of an exponent. As you will see, things cancel out more nicely this way.

Take the natural log of both sides:

Rewrite the right-hand side of the equation using the product rule for logs:

Now rewrite the whole equation after bringing down those exponents.

is the same thing as , which equals 1.

Now we just divide by on both sides to isolate .

Example Question #1 : Natural Log

Rewrite as a single logarithmic expression:

Possible Answers:

Correct answer:

Explanation:

Using the properties of logarithms

 and ,

we simplify as follows:

 

Example Question #1 : Natural Log

Which of the following expressions is equal to the expression  ?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

By the reverse-FOIL method, we factor the polynomial as follows:

Therefore, we can use the property 

as follows:

 

 

Example Question #1 : Natural Log

Solve . Round to the nearest thousandth.

Possible Answers:

Correct answer:

Explanation:

The original equation is:

Subtract  from both sides:

Divde both sides by :

Take the natural logarithm of both sides:

Divde both sides by  and use a calculator to get:

 

 

Example Question #1 : Natural Log

What are the domain and the range of the function ?

Possible Answers:

Domain = all positive numbers

Range = all positive numbers

Domain = all positive real numbers

Range = all real numbers

Domain = all non-negative numbers 

Range = all positive numbers

Domain = all real numbers 

Range = all real numbers

Domain = all positive numbers 

Range = all non-negative numbers

Correct answer:

Domain = all positive real numbers

Range = all real numbers

Explanation:

Remember that  is still a logarithm of a positive number, .

It's not possible to raise  to ANY power and obtain a negative number. Because even , for example, is just , which is a ratio of two positive numbers, and therefore positive.

More than that, it's also not possible to obtain 0 by raising  to any power. Think: "To what power can I exponentiate e and obtain 0?"

So the domain is strictly positive. It excludes negative numbers and 0.

 

What about the range? To what possible values are we allowed to exponentiate ?

Well, we just saw that  has a definition for negative numbers.  (this fact is true for ALL numbers, not just ).

And we can obviously raise it to positive powers. So the range is all real numbers. It includes negative numbers, 0, and positive numbers.

Example Question #2 : Natural Log

Solve for :

.

If necessary, round to the nearest tenth.

Possible Answers:

No solution

Correct answer:

Explanation:

Give both sides the same base, using e:

.

Because e and ln cancel each other out, .

Solve for x and round to the nearest tenth:

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