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urp:algebra [2021-11-08] nerf_herder |
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====Algebra & Pre-Calc==== | ====Algebra & Pre-Calc==== | ||
+ | Related pages: | ||
* [[Graphing|Graphing circles, ellipses, parabolas, hyperbolas]] | * [[Graphing|Graphing circles, ellipses, parabolas, hyperbolas]] | ||
* [[poly|Polynomials, quadratic formula and completing the square]] | * [[poly|Polynomials, quadratic formula and completing the square]] | ||
**quadratic formula**: x = (-b ±√(b²-4ac)) / 2a | **quadratic formula**: x = (-b ±√(b²-4ac)) / 2a | ||
+ | |||
+ | **PEMDAS/BODMAS ** - order of operations: Parentheses/Brackets, Exponents/Order, Multiply-Divide, Add-Subtract | ||
==== System of equations==== | ==== System of equations==== | ||
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(nᵃ)ᵇ = nᵃᵇ | (nᵃ)ᵇ = nᵃᵇ | ||
n⁻ᵃ = 1/nᵃ | n⁻ᵃ = 1/nᵃ | ||
+ | |||
+ | (Note: The square root sign, √, refers only to the //positive// root. Use ± to include both roots.) | ||
Factorial: | Factorial: | ||
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==== Logs ==== | ==== Logs ==== | ||
- | inverse of a power | + | Log is the inverse of a power |
x = bᵉ, e = logᵦ(x) (b = base, 10 by default) | x = bᵉ, e = logᵦ(x) (b = base, 10 by default) | ||
eg. 2³ = 8, log₂(8) = 3 | eg. 2³ = 8, log₂(8) = 3 | ||
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composition of functions: (f’g)(x) = f(g(x)), order of evaluation is important | composition of functions: (f’g)(x) = f(g(x)), order of evaluation is important | ||
- | inverse of function - only possible if no two values of x produce the same result | + | |
- | graphing an inverse: reflection of the graph about the line y=x | + | **Inverse** of a function - only possible if no two values of x produce the same result, ie. must be one-to-one (or limit the domain to make it so) |
+ | Example: To find f⁻¹(x) for f(x) = 5x + 3 | ||
+ | y = 5x + 3 | ||
+ | y-3 = 5x | ||
+ | x = (y-3)/5 | ||
+ | f⁻¹(x) = (x-3)/5 (replace y with x on the last step, | ||
+ | since x is input to the function, and y is output) | ||
+ | |||
+ | Graphing an inverse: reflection of the graph about the line y=x | ||
**horizontal and vertical asymptotes:** | **horizontal and vertical asymptotes:** |