Borland Educational News and Views: 12/01/2024

Sunday, December 08, 2024

Exponent Rules

After addition, subtraction, multiplication, and division, exponentiation serves as the 5th and final arithmetic operation.

Calculations involving exponents are crucial in algebra and are a major feature of SAT/ACT math. Seven basic rules and two additional corollaries govern exponentiation.

It’s important to understand these principles well and master their use through practice and application.

Below are the laws governing exponents you'll need to know and follow.

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Basic Exponent Rules (A ≠ 0, B ≠ 0)

Product of Equal-Base Powers: A^m*A^n = A^(m+n)
c: z^3*z^4 = z^7.

Quotient of Equal-Base Powers: A^m/A^n = A^(m–n).
For example: x^-3/x^5 = x^-8.

Power of a Power: (A^m)^n = A^(mn)
For example: (y^3)^4 = y^12.

Power of a Product: (A*B)^n = (A^n)(B^n)
For example: (x^2*y)^3 = (x^6)(y^3).

Power of a Quotient: (A/B)^n = [(A)^n]/[(B)^n]
For example: (x^7.5/y^-2)^2 = [x^15]/[ y^-4].

Zero Powers: A^0 = 1 (A ≠ 0)
For example: (2z–1)^0 = 1 (z ≠ 1/2).

Negative Powers: A^-n = 1/(A^n)
For example: x^-3 = 1/(x^3).

Additional Corollaries

Quotient of Negative Powers: A^-m/B^-n = B^n/A^m
For example: y^-1/z^4 = z^-4/y^1.
(Changing positions of the lower and/or upper powers changes the signs on those exponents)

Negative Power of a Quotient: (A/B)^-n = (B/A)^n
For example: (x^-1/y^8)^-4 = (y^8/x^-1)^4.

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For practice, search Google for “exponent rules worksheet,” pick a worksheet that provides answers, complete the worksheet, analyze any mistakes, and redo it until you can complete that worksheet with no errors. Then repeat, with additional worksheets, as needed, until you’ve mastered this material.

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Contact Chris

borlandeducational.com

Sunday, December 01, 2024

General Functions – What You Need to Know

Much of high school algebra revolves around the study of input/output machines called functions, one of the most widely applicable concepts in all mathematics. Naturally, functions comprise a large fraction of questions found on the SAT/ACT. Fortunately, only knowledge of basic facts and processes is required.

Here’s what you need to know, generally, about functions.

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[Note: “iff” means “if and only if.”]

Definition

A function is a relationship between two sets of numbers, one containing inputs and the other for outputs; these sets are called "the domain" and "the range," respectively. A function can can be understood as an input/output “machine” that takes a number in and returns a corresponding number out, such that no input is associated with more than one output. Normally, the input is called x and the output is called y. The function itself is named with a single letter, like f, in which case the output for general input x can be written “f(x),” pronounced “f of x.”

y = f(x)
y and f(x) are interchangeable.

Function values
The “value of a function” is an output value (y value).

Operations
The essential operation with functions is substitution.
“g(n)” means substitute n for x in function g.

Composition of Functions
Composite functions are “nested” functions. “f[g(x)]” means function g is nested inside function f.
For example: To find f[g(2)], first find g(2) and then substitute that value into f.

Zeros of a function
Values of x (input values) that make y (output values) equal zero.
Zeros are found at x-intercepts.

When f(x) = 0, solutions are called “roots.”

Solutions iff roots iff zeros iff x-intercepts (“roots,” “zeros,” “solutions,” “x-intercepts” are essentially synonymous).

Intercepts of functions:
To find intercepts, let the other variable’s value be zero

For example: For the y-intercept, let x = 0).

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For practice, search Google for worksheets covering any or all of the above, pick a worksheet that provides answers, complete the worksheet, analyze any mistakes, and redo it until you can complete that worksheet with no errors. Then repeat, with additional worksheets, as needed, until you’ve mastered this material.

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Contact Chris

borlandeducational.com