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#1 Re: Help Me ! » Word Problems: Multiplying Fractions » 2017-01-17 03:46:01

Obviously, you want 1/2 of 3/4 of old fashioned oats for making 1/2 of the recipe.  Maybe what it isn't so obvious is that division by 2 gives the same result as multiplication by 1/2: 

To make sense of the above, remember that any number can be rewritten as the number over 1...

...and to get half of something, we have to divide it by 2...

...which can be rewritten as a multiplication...

And so...

#2 Re: Help Me ! » The quadratic formula » 2017-01-11 08:16:03

Bob, that is a very clear explanation.  Thanks for taking the time.

#3 Help Me ! » The quadratic formula » 2017-01-10 16:41:08

Replies: 2

I came across a video in which the author explains visually how to arrive at the quadratic formula, except he skips some steps.

Here is the video:

I follow it up to this point, where some steps are skipped:

In the video, the right side of the equation goes from: 


So I think that I can rewrite the first example like this: 

But I don't see how the a can be moved to the numerator.  Or maybe I'm approaching it all wrong.

By the way, I really like this approach to explaining math.  I never understood what 'completeing the square' actually means until I saw this video.  It seems right at home with so many of the nice explanations here at Math is Fun.

Side note:  I really appreciate the LaTeX integration in the forum.  This is nice!

#4 Re: Dark Discussions at Cafe Infinity » What is EM? » 2016-12-19 06:01:27

Agnishom wrote:

I like writing too. Have you seen my notes?

They could be hidng in a piano, or other such place.

#5 Re: Dark Discussions at Cafe Infinity » What is EM? » 2016-12-18 20:20:18

Agnishom wrote:


A main ingredient in ghoul gravy, which gained popularity shortly after the development of the modern crematory.


#6 Dark Discussions at Cafe Infinity » What is EM? » 2016-12-18 12:54:03

Replies: 66

I assume that it is an abbreviation for, <something> math.

#8 Computer Math » Plotting vertical line in Geogebra? » 2016-12-12 06:41:28

Replies: 3

I'm relearning algebra after some years of being away from school, and I'm learning to use Geogrebra.  At the moment I'm plotting some lines to get a sense of what elementary functions look like on a grid.  I never really got a good sense of this when I was in school.

So I have:

f(x) = x , which gives a diaganol line.
f(x) = -x , which gives a mirror of the above diagonal line (Is there a math term for this?).
f(x) = 0x , which gives a horizontal line.

How would I plot a vertical line?  The closest that I have found is:

f(x) = 10^(100)x

#9 Introductions » Hello people of mathisfun » 2016-12-12 06:27:39

Replies: 3

Great site.  I have been visiting here sporadically over a couple of years, and it is always a good experience.  I guess it is about time that I joined the forum.  Thanks to everyone who contributes to the site and discussion on the forum.

About myself:  I am an adult who never learned much math outside of basic algebra.  I am going back and relearning algebra, looking at going much further.  My interests in math stem from interests in music, electronics, programming, carpentry, and other areas.  And I am coming around to finding out that math is interesting in it's own right.

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