From Omilili

**Matrices** - Area Scale Factor

Hi guys, I have another **matrices**question. The rectangle R has vertices at the points (-1,0),(0,-3 can find that the answer to this is: (

**2**,-1), (3a-9,-3a), (-8,4) and (3-3a,3a+3) b) Find det that should equal A = 15. As a further problem down the road. I do not get a =

**2**. I am getting a = -8

From Yahoo Answers

**Question:**I have a science project, and i have all my stuff built for a model earthquake, i need to find a way on how to measure my force of the earthquake, so i can do like a magnitude 5 earthquake or around there. So my project their will be a house on top of a block of wood, which will be going back and forth, until the house breaks, but how do i know how much the earthquake is "damaging"(not sure what word to use) Ex. Magnitude 1-10 earthquake, anyway possible is fine. Thank You

**Answers:**Richter scale is used to measure the energy released during earthquakes from the point called focus. To measure this Mr Charles Richter has found a method .It is called Richter scale. He was using Wood Anderson seismic meter to measure the shaking . It is little bit complicated. The energy release increases by 31.7 times for each Richter scale .But the amplitude of shaking increases by ten times for each Richter scale and getting reduced by inverse square of distance from epicenter. You can use the maximum amount of shaking to gether with the distance of epicenter. To find the distance of epicenter you need to know the arrival time of P wave and S wave and its speed difference.However I am giving below the formula. For body wave mb = log V p-wave +0.01delta+5.1 For surface wave Ms = log V surface-wave + 1.66log delta+2.5 where V is the velocity of the wave in micrometers/sec, and (Delta) is the angular epicentral distance in degrees.

**Question:**A line-line voltage v is applied to a 3-phase commercial load and the resulting current is found to be i. Find the power factor of the load, the average power in kW absorbed by the load and the frequency of the alternating voltage. (Note: The arguments of the cosine are in radians.) v= 241cos(338t+0.42)v i= 16.93cos(338t)A power factor = cos so far i just know P=VIcos as its formula...any advice is welcomed.

**Answers:**Power factor is defined as the cosine of the angle between current and voltage. pf = cos(338t - 338t + 0.42) pf = cos(0.42) pf = 0.913 The answer makes sense in a real world application as well.

**Question:**how do you find factors of large numbers which will be the sum or difference of another number? Example: what are the factors of 4860 when added together will be the sum of -63? I mean, how would you know where to start cuz the number is large. If i would do trial and error with numbers it takes a really long time. Please help.

**Answers:**if the number is even then its divisible by 2. if the sum of the num is divisible by 3, then the num is divisible by 3. if the last two digits of a number is divisible by 4, then the num is divisible by 4, if the num ends in 0 or 5 its divisible by 5 and so on...

From Youtube

### SLEP Find Prime Factors

Examples how to..### How to Find the Greatest Common Factor

Expand the description and view the text of the steps for this how-to video. Check out Howcast for other do-it-yourself videos from stevenkittinger and more videos in the Mathematics Tests category. You can contribute too! Create your own DIY guide at www.howcast.com or produce your own Howcast spots with the Howcast Filmmakers Program at www.howcast.com The methods for finding the greatest common factor for a series of numbers and for an algebraic expression are similar. To complete this How-To you will need: A series of numbers Algebraic expressions Step 1: Determine for a series of numbers Factor each number in a series of numbers completely into its primes; identify the common factors for each number; and then multiply the common factors together. Tip: A prime number is a positive integer that is not itself the product of two smaller positive integers. Step 2: Use 18 and 27 Use the numbers 18 and 27 as an example. The primes of 18 are three, three, and two. The primes of 27 are three, three, and three. So the greatest common factor is three times three, or nine. Step 3: Determine the greatest common factor for algebraic expressions Identify all of the common factors in a series of algebraic expressions. Step 4: factor 60x2y and 210xy2 Use the expressions the common factors of the first expression are two, two, three, five, x, x, and y. The common factors in the second expression are two, three, five, seven, x, y, and y. So the greatest common factor is two times three**...**