Algebra: Chapter 12, Lesson 7, page 565.
Joint and Combined Variation
An equation of the form `z = kxy`, where `k` is a constant, expresses joint variation. An equation of the form `z = (kx)/y` expresses combined variation. There are 2 steps involved when solving these equations.
- Find `k`, by using all other information given. If there are 2 other variables, then values for those variables must be provided.
- Using the value of `k` that you calculated, and just one of the other variables with NEW values, you can solve for the unknown variable.
Examples 1, 2 and 3 in the textbook walk you through the steps as well.
This link from purplemath.com has more info too.
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Algebra 1a: Chapter 5, Lesson 4, page 217.
Scientific Notation
We can write numbers as the product of a power of 10 and a number greater than 1 but less than 10 (9.9999…. to be exact). Standard notation is the stuff that we are normally used to.
Examples: `4.58 × 10^4=45,800`
`(3.0 × 10^5)(4.1 × 10^(-3))=(3.0⋅4.1 ) * (10^5 × 10^(-3))=12.3 × 10^2=1.23 × 10^3`
`(2.5 × 10^(-7))/(5.0 × 10^6) = (2.5/5.0) * (10^(-7)/10^6) = 0.5 × 10^(-13) = 5.0 × 10^(-14)`
More scientific notation examples are here.
Two of tonight’s homework problems solved by MrE are here! Just click it!