- Submitted By: KrAt0S
- Date Submitted: 08/07/2013 2:56 AM
- Category: Miscellaneous
- Words: 308
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Math Stuff

Although this guide is for the SAT Subject test in Physics, you’ll need to know quite a bit

of math. If you’re thinking that you’ll just use your calculator to do the math, don’t forget

that calculators are not allowed on the SAT Subject Physics test . Here is a summary of

the really important math facts and formulas.

Exponents

xa · xb = xa+b

(xa)b = xa·b

x0 = 1

xa/xb = xa−b

(xy)a = xa · ya

√xy = √x · √y

1/xb = x−b

(−1)n =

+1, if n is even;

−1, if n is odd.

Scientific Notation

Scientific notation is a short-hand form to write numbers which would have a lot of zeros

when written as decimals. For example, instead of writing 1230000, you can just write

1.23 × 1000000, or 1.23 × 106. The familiar powers of ten include:

10−3 = 0.001, 10−2 = 0.01, 10−1 = 0.1, 100 = 1, 101 = 10, 102 = 100, 103 = 1000.

To go from scientific notation to a plain decimal number, move the decimal to the right

or left according to the sign of the exponent, putting a zero down when you have no other

digits there. For example, for 3.7 × 1012, move the decimal right 12 places and add 11

zeros. Move the decimal to the left for a negative exponent.

37

11 zeros z }| {

00000000000 . = 3.7 × 1012

. |00000{z00000}

10 zeros

23 = 2.3 × 10−11

To go from a plain decimal number to scientific notation, just move the decimal to the

right or left (counting how many places you move) until there is only one digit to the left

of the decimal point, then add “ ×10n ” where n is the number of places you moved the

decimal point (positive if you went left and negative if you went right).