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#51 Re: Help Me ! » Quadratic equation » 2024-05-24 07:35:09
Mathxyz okay and thanks.
Professor Leonard is probably the best math professor online.
#52 Re: Help Me ! » Quadratic equation » 2024-05-23 15:52:37
Thanks all, looks like i would have to spend more time on Algebra.
Copy and paste this link:
https://m.youtube.com/watch?v=bNxtxiN-FtI&pp=ygUlUHJvZmVzc29yIGxlb25hcmQgcXVhZHJhdGljIGVxdWF0aW9ucw%3D%3D
#53 Re: Help Me ! » Number Zero » 2024-05-23 15:48:57
For infinity discussion, I refer you to my post: https://www.mathisfunforum.com/viewtopic.php?id=31062
Thanks. Will do.
#54 Re: Help Me ! » Number Zero » 2024-05-23 08:34:55
3 and 4 are obvious. 1 and 2 ? Shouldn't really have these as infinity doesn't obey the four rules of arithmetic. But there could be a context where it makes sense
eg what is the value of x times 1/( x^2 + 2) as x tends to infinity. Here the method is to attempt to simplfy first.
As x^2 is getting very large the + 2 has a negigible effect so we can approximate the expression as x times 1/x^2 = 1/x
So we can see that, in this case, the expression tends to zero as x tends to infinity.
But there no general rule here; you have to simplify each expression separately.
eg (x^2 + 2) times 1/x gives a different answer.
Bob
Cool. Very good.
#55 Re: Help Me ! » Number Zero » 2024-05-22 11:43:59
Why does zero times anything equal zero?
I guess x times y means how many lots of y you have
2 times y means you have 2 lots of y
10 times y means you have 10 lots of y
Zero times y means you have zero lots of y
You have no lots of y
You have no y
I get it.
What does the following mean?
Let 00 stand for infinity.
1. What is 0 • 00?
2. What 0 • -00?
3. What is 0 + 00?
4. What is 0 - 00?
#56 Re: Help Me ! » Equilateral Triangle » 2024-05-22 08:57:39
This is made easier because the given points lie on the y axis.
Find the midpoint. A line perpendicular to this will go through the third vertex. So you can say what it's y coordinate is. Call it's x coordinate 'x' and use the distance formula (distance will be = 4) to find x. Two solutions.
Bob
Sounds good. I will also do this on paper and only return here if I get stuck.
#57 Re: Help Me ! » Find Lengths of the Medians » 2024-05-22 08:56:10
1. won't help
2. yes. Once you have a midpoint calculate the distance from that point to the opposite vertex. Repeat two more times for the other midpoints.
Bob
Ok. That is easy. I will work it out on paper.
#58 Re: Help Me ! » Find Coordinates of Point B » 2024-05-22 08:55:03
That works for me.
Bob
Cool. Change of plans.
A. We stick to one textbook at a time. Right College Algebra only Edition 9 Sullivan.
B. Math questions will be posted on my days off only (when time allows).
#59 Re: Help Me ! » Find All Points » 2024-05-22 08:52:54
This question is on page 41 in my copy of the book. Mine has pages of introductions before the first lessons and questions. 41-7 = 34. Maybe I'll have to apply a transformation of (my page = (your page) + 34 to find the questions.
The distance formula comes directly from Pythagoras' theorem, so I would end up with the same equation using either.
Let the point be (x,-6)
(x-1)^2 + (-6-2)^2 = 17^2
Solve for x, two solutions.
Bob
Do you have Edition 10 of the book? I you have another edition, the problems are located on different pages. In Edition 10, the problem is on page 7. I will work this out on paper. No more math for the rest of the week.
#60 Re: This is Cool » A Point Cannot Be Measured » 2024-05-22 08:48:24
Ok do you want me to measure the size of the point? or measure where the point is on the paper?
I can measure where the point is on the paper with a simple ruler. Measure the circumference, radius and diameter of the DOT, you know, the DOT on your paper. Find the area of the DOT, the DOT itself.
#61 Help Me ! » Equilateral Triangle » 2024-05-21 23:44:06
- mathxyz
- Replies: 2
Problem 56; page 8.
Precalculus.
An equilateral triangle is one in which all three sides are of equal length. If two vertices of an equilateral triangle are (0, 4) and (0, 0), find the third vertex. How many of these triangles are possible?
For this one I do need the first-two steps.
1. How do I find the third vertex?
2. How many of these triangles are possible?
#62 Help Me ! » Find Lengths of the Medians » 2024-05-21 23:36:13
- mathxyz
- Replies: 2
Problem 55; page 7.
Precalculus.
The medians of a triangle are the line segments from each vertex to the midpoint of the opposite side. Find the lengths of the medians of the triangle with vertices at A = (0, 0), B = (6, 0), and C = (4, 4).
Let me take a guess.
1. I must distance between each given point.
2. Find the midpoint between each given point.
Yes?
#63 Help Me ! » Find Coordinates of Point B » 2024-05-21 23:29:32
- mathxyz
- Replies: 2
Problem 52; page 7.
Precalculus book.
Plot the points A = (-1, 8) and M = (2, 3) in the xy-plane. If M is the midpoint of a line segment AB, find the coordinates of B.
Let me try this one.
Midpoint Formula:
M = [(x_1 + x_2)/2, (y_1 + y_2)/2]
Let point B = (x_2, y_2).
2 = (x_1 + x_2)/2
2 = (-1 + x_2)/2
4 = = -1 + x_2
5 = x_2
Same process to find y_2.
3 = (y_1 + y_2)/2
3 = (8 + y_2)/2
6 = 8 + y_2
-2 = y/2
I say the coordinates of point B are (5, -2).
Yes?
#64 Help Me ! » Find All Points » 2024-05-21 23:19:16
- mathxyz
- Replies: 2
Problem 48; page 7
Precalculus book.
Find all points having a y-coordinate of -6 whose distance from the point (1, 2) is 17.
A. By using the Pythygorean Theorem.
B. By using the distance formula.
When it comes to problems that I don't know how to solve, I always request the first-two steps.
#65 Re: This is Cool » A Point Cannot Be Measured » 2024-05-21 22:21:05
mathxyz wrote:AnthonyRBrown wrote:There is no such thing as "must be accepted"! where I come from,for me that is like a Red flag to a Bull
My whole life has been driven by proving that wrong! and many others who naturally think outside the box,can you imagine how many great inventions,acheivments,scientific breakthroughs,etc. that would have been missed if all.those people took notice of the "must be accepted"
Perfect. Now you can prove mathematically why a point has no measure. We are all waiting for this great mathematical feat.
mathxyz I think you have misunderstood the type of person I am,I am not driven by "trying to prove mathematically why a point has no measure."
I am driven by proving mathematically why a point has a measure!
So the first questions for you is...Can the point you are talking about be seen? or is the point you are talking about an imaginary point?
Ok. Cool. Take your pencil or pen and tap a piece of paper once, quickly and hard. You will see a point on the paper. Now, measure the point. If you do that successfully, you will be the first human on the planet to find the measurement of that tiny, little dot. There you go: by point I mean dot.
#66 Maths Is Fun - Suggestions and Comments » More Math Forums By Category » 2024-05-21 21:02:31
- mathxyz
- Replies: 1
I think more math forums should be added and some of the unpopular forums renamed or deleted.
Here are 5 forums that should be added to this site by category:
1. Prealgebra
2. Algebra 1
3. Algebra 2
4. Geometry
5. Trigonometry
You say?
#67 Maths Is Fun - Suggestions and Comments » Math Video Lessons Forum » 2024-05-21 20:59:00
- mathxyz
- Replies: 0
How about a math video lesson forum?
#68 Help Me ! » Number Zero » 2024-05-21 20:55:03
- mathxyz
- Replies: 6
The Mayans defined zero as the absence of value.
1. What is your definition of zero?
2. Why does zero times anything equal zero?
#69 Maths Teaching Resources » Math For Dummies Series » 2024-05-21 20:46:55
- mathxyz
- Replies: 4
What are your thoughts concerning the math for dummies book series?
Examples:
Algebra For Dummies
Precalculus For Dummies
Etc.........
#70 Dark Discussions at Cafe Infinity » Secure or Secured? » 2024-05-21 20:42:43
- mathxyz
- Replies: 0
Concerning the words secure and secured, give two sentences for each word.
I will give one for each.
Secure
Jenny felt secure at her new office job.
Secured
Rick secured the beach house door before leaving this morning.
#71 Re: Maths Is Fun - Suggestions and Comments » Suggestions? For what? » 2024-05-21 18:32:28
mathxyz wrote:Jai Ganesh wrote:The posts are deleted over and over again isn't a fact. The number of posts over a period of 10 days from this day by this member can be verified. Number of posts have been abnormally high by this member. Before posting, one must verify the facts.
Moreover, as Administrator, it is my responsibility and I have the discretion, in the interests of the forum and forum members.
You must be bored. You can skip my posts. Right? Easy thing to do.
The issue may be treated closed. And learn to be polite.
Polite? Really? I must be polite but others don't have to be polite to me. Cool.
#72 Re: This is Cool » A Point Cannot Be Measured » 2024-05-21 18:23:32
mathxyz wrote:AnthonyRBrown wrote:Ok so I have an idea on how a point can be measured...
So we attached the amount of ink that was going to be used to write a point,to the end of a needle then we drop the ink onto an Atomic weighing scale,this should give us an accurate measurment of a point!
A point cannot be measured is a definition in Geometry that must be accepted as truth.
There is no such thing as "must be accepted"! where I come from,for me that is like a Red flag to a Bull
My whole life has been driven by proving that wrong! and many others who naturally think outside the box,can you imagine how many great inventions,acheivments,scientific breakthroughs,etc. that would have been missed if all.those people took notice of the "must be accepted"
Perfect. Now you can prove mathematically why a point has no measure. We are all waiting for this great mathematical feat.
#73 Re: Help Me ! » Dividing A Polynomial By x - c » 2024-05-21 14:32:06
(1) I plan my test time better than that so I'd have 10 minutes.
(2) Because I can see all the powers of x and I'm very neat with the layout I'm much less likely to make an error.
(3) I hate learning new stuff so if I've got a working method I like to stick to it.
Bob
Ok. Very good. You are smart.
#74 Re: Help Me ! » Is (x - c) a Factor? » 2024-05-21 14:31:04
OK, I get it now. I was in the wrong textbook.
Your working is correct.
Factor theorem: put x=2 in 4x^4 - 15x^2 - 4 = 64 - 60 - 4 = 0 => x-2 is a factor.
Bob
Very good. Thank you for your time and dedication to the site.
#75 Re: Help Me ! » Dividing A Polynomial By x - c » 2024-05-21 09:12:57
I agree - long division. Synthetic, while a cool idea that it works, is unnecessary, and for students with so much else to learn in the course, just a lot of clutter.
What if you are taking a test and there are 5 minutes left?
Synthetic division leads you to the answer faster in place of guessing incorrectly.
You say?