PSAT Math : Exponents

Study concepts, example questions & explanations for PSAT Math

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Example Questions

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Example Question #262 : Exponents

Simplify:

Possible Answers:

Correct answer:

Explanation:

Now

Hence the correct answer is

Example Question #261 : Exponents

Solve for .

Possible Answers:

Correct answer:

Explanation:

If we combine into a single logarithmic function we get:

 

 

Solving for  we get .

Example Question #261 : Exponents

If  is the complex number such that , evaluate the following expression:

Possible Answers:

Correct answer:

Explanation:

The powers of i form a sequence that repeats every four terms.

i= i

i2 = -1

i3 = -i

i4 = 1

i5 = i

Thus:

i25 = i

i23 = -i

i21 = i

i19= -i

Now we can evalulate the expression.

i25 - i23 + i21 - i19 + i17..... + i 

= i + (-1)(-i) + i + (-1)(i) ..... + i

= i + i + i + i + ..... + i

Each term reduces to +i. Since there are 13 terms in the expression, the final result is 13i.

Example Question #1241 : Psat Mathematics

Express 0.000000076 in scientific notation.

Possible Answers:

Correct answer:

Explanation:

Write the number:

Counting the number of places, move the decimal point to the right until it is after the first nonzero digit:

The resulting number is 7.6; the number of places the decimal point moved to the right was 8. In scientific notation, this number is .

Example Question #581 : Algebra

Express the square of  in scientific notation.

Possible Answers:

Correct answer:

Explanation:

Take advantage of the exponent rules.

Example Question #141 : Exponents

The number  is equivalent to which of the following?

Possible Answers:

Correct answer:

Explanation:

Each of the answers to this question are in scientific notation. To determine the exponent on the 10, see how many places you need to move the decimal over to get from your original number to 2.79.

Scientific_notation

Because the decimal place moves 5 places, the exponent will be 5, and because the decimal moves to the RIGHT, the exponent is going to be negative.

So the answer to the quesiton is 

Example Question #4 : How To Use Scientific Notation

Put the following value in scientific notation:

Possible Answers:

Correct answer:

Explanation:

Our first value for scientific notation should be between  and . We then multiply this value by  raised to a power equal to the number of spaces our decimal has moved to the left.

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