Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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#2 Re: Help Me ! » Image test » Yesterday 01:51:45

Bob

All hail the laptop.  Better all round.  But not so portable.  Airport security is particular about anything above phone size.  Schiphol; did I mention don't use it as you spend your life queuing; wanted me to remove the handkerchief from my pocket so they could scan it. WHAT!

I followed the link. We seem to have already had this conversation. Worryingly, I don't remember a thing from that thread.  I'm hoping Imgur will come up with a bcc update soon.

Bob

#3 Re: Help Me ! » Image test » Yesterday 00:09:59

Bob

Hi Phro,

I'm using Android.  Tried all sorts of image sharing but have yet to get the bcc version. Elsewhere on the help it says bcc is not an option for mobiles


Bob

#4 Help Me ! » Image test » 2022-09-30 21:11:49

Bob
Replies: 14

I am trying Phrontister's method for creating an Imgur image.

step 1. On my mobile, log in to Imgur and select an image.

step 2. Bottom right of screen, click the arrow and choose copy URL.

This is that url.

https://imgur.com/a/BURsC8w

If I enter it into my laptop browser address bar I can view the image. I'm not logged in to Imgur on my laptop so I assume anyone can do this.

step 3. On my laptop right click the image and choose 'copy image link'

step 4.  I then pasted that back into this post. Here is the link:

https://i.imgur.com/7RjDiAX.jpeg

Note. It is different to the above and has jpeg as an extension.

step 5. Add bcc code to make the image appear. open square bracket, img close square bracket; image link address;open square bracket /img close bracket.  Here is the resulting image.

7RjDiAX.jpeg

So, if a member is limited to a mobile I can convert their image so it appears in their post. They would have to do steps 1 and 2, and I'd have to do the rest.

Remaining question. Can steps 3 - 5 be done on a mobile?  Still working on that.

Bob

#5 Re: Help Me ! » Find Domain & Range » 2022-09-30 19:44:53

Bob

hi imcute

As you are new you perhaps won't have been following the difficulty here over a number of threads.  On a previous server it was posssible to upload images directly to MIF but difficulties with that server meant the forum had to swiitch over and the direct upload facility was lost.

I use Imgur to get images here using a bcc code address from Imgur.  I advised harpazo1965 to do the same.  He signed up and uploaded his image there but the site does not support bcc on their mobile app, so this hasn't helped him.

If you know a way to get an Imgur image into bcc format on a mobile we'd all be really pleased to know it.  Or maybe you know another way for him to get images here.  Thanks.

Bob

#6 Re: Help Me ! » Exponential and Logarithm functions » 2022-09-30 19:37:26

Bob

hi imcute

Welcome to the forum.

I think zetafunc was trying to encourage Jade to work it out for herself.  If you want her to undetstand (and I know she is keen to learn not just have the answers) then please develop your formula so the whole method becomes clear. Thanks.

Bob

#7 Re: Help Me ! » Even, Odd or Neither » 2022-09-30 19:33:52

Bob

Tried this and I get an Imgur 404 error.

Bob

#8 Re: Help Me ! » Unbounded Intervals » 2022-09-30 19:32:06

Bob

hi everyone,

My apologies for not being able to post properly the other day.  I was away from home just using a Samsung A21s mobile and a hotel wifi.  I don't like to openly state that I'm not at home so I had to be cryptic.  After a two hour queue (no exageration) at Schiphol airport in the line for security (the start wasn't even in the building!) I am now back on my laptop.

I see there have been developments.  The first post gave a link which didn't work on my mobile. But it did for Phrontister and he was able to convert so that it showed in his post.  So we were part way to a method to get images .  But that link now gives a 'no such address' error.  Either harpazo1965 has deleted it or imgur have moved it.  Odd.

Let's not waste any more time on that one.  I answered the question in post 4 and the definition, if you really want one, would have to be      -∞ < x  < +∞.

That's like saying x is a real number such that x is a real number.  True but not really adding anything useful.

I noticed while away that there are some more posts with images so I'm going to switch to one of those and see if I can get the image showing.

Bob

ps. How many posts are you allowed to make? I don't think there is a limit, but please use some common sense. If you post lots of questions I won't have time to answer them all.  If you post too much chat, you're in danger of breaking the spam rule.

#9 Re: Help Me ! » Find Range of Rational Function » 2022-09-29 06:49:56

Bob

That should work but I still think the graph is the key. Once you have that the algebra is easy.

Bob

#10 Re: Help Me ! » Unbounded Intervals » 2022-09-29 06:44:37

Bob

I cannot explore any at the moment.  I'll work on these in a couple of days.

Bob

#11 Re: Help Me ! » Unbounded Intervals » 2022-09-28 04:03:52

Bob

Many thanks, Phro.  That's just what I needed. I'm gong to take out your hide tags to see if the image shows as was wanted.  If so, you have found a way to get the image onto MIF from imgur. Yay! It works!

As to the poster's question its simply this.  All x lies between minus infinity and plus infinity so why waste space including an inequality.

Bob

#12 Re: Help Me ! » Unbounded Intervals » 2022-09-27 20:02:54

Bob

Sorry  I'm not seeing anything on that address.  Are you able to text more details of this problem?

Bob

#13 Re: Help Me ! » Find Range of Rational Function » 2022-09-27 19:31:48

Bob

It's got a vertical asymptote at x=3. And a horizontal one at y=1.

If you attempt to solve for y=1 you get no x value.

So that's a clue. Try to construct the graph


Bob

#14 Re: Help Me ! » Find Domain of Function » 2022-09-26 18:12:36

Bob

That answer is good.

I have addressed your suggestion in your other post.

Bob

#15 Re: Exercises » Math Homework Questions From Student Days » 2022-09-26 18:11:10

Bob

There is a on-line maths course that objected because we were 'publishing' their worksheets. They threatened 'breach of copyright' action.

So you need to take care what you post.  If you have a question that you think is good practice for a particular exam, post it in Exercises. Post one question at a time rather than collecting up a whole set and posting all in one go.

Bob

#16 Re: Maths Is Fun - Suggestions and Comments » Math Entry Test » 2022-09-26 18:05:47

Bob

I am totally opposed to this.  The forum is open access. Lots of our members join because they are weak at maths and want help to improve.

Bob

#17 Re: Help Me ! » Find Domain of Function » 2022-09-26 04:52:37

Bob

hi harpazo1965

For my question you have correctly identified two values that are outside the domain.

The vertical lines x =-1 and x = + 1 are asymptotes.  If you're not sure what that means have a look at Jade's post about a domain and range question here:

http://www.mathisfunforum.com/viewtopic.php?id=27953

My initial answer was limited because I was only working from a phone.  Later I was able to add a graph that, I think, makes it clearer.  I would certainly say that the graph is the key to domain and range questions.

Looking at your final answer you don't say what happens between the asymptotes ... ie between -1 and + 1.  Do you think there are no x values there?  Easy to show that's wrong because x = 0 gives y = -5.

I'll leave you to ponder that.

Bob

#18 Re: Help Me ! » Find Equation of Circle » 2022-09-25 19:45:03

Bob

Some posters send in their entire homework sheet in the hope they'll be given all the answers.  We don't do that here.

A quick glance at post 1, might give the impression harpazo1965 had done this, but I spotted that, in fact, he had just posted a single question; had gone on to attempt it himself; and was merely asking if it was correct.  It looks to me that any problem with this thread resulted from a misunderstanding.  Let's move on.  I will close this thread.

Bob

#19 Re: Help Me ! » Find Domain of Function » 2022-09-25 19:34:28

Bob

hi

In questions about domain the assumption is that it will be all real numbers unless there are values of x that do not lead to values of y.

infinity is not a value that y can ever attain.

This is why you set the denominator to zero to see if x vales might lead to the graph 'zooming' up towartds infinity. You didn't find any so no reason not to have the whole set of real numbers as the domain.

The 'rule' is all reals unless there is a good reason to exclude some x values.

There are other reasons.  For example the square root function has to be limited to x ≥ 0 as you cannot find a real number that is the square root of a negative.

If you wanted to devise a function to calculate the cost of theatre tickets  where the input is 'n' the number of people wanting tickets you'd have to exclude everything except whole numbers . You might allow zero and you might have a top limit to n based on the size of the venue.

Try y = 5/x^2-1) for comparison.

Bob

#20 Re: Help Me ! » Find Equation of Circle » 2022-09-24 19:50:45

Bob

hi harpazo1965

(x - 1)^2 + (y + 2)^2 = 9 is correct. Well done!

Bob

#21 Re: Help Me ! » Solve for x » 2022-09-23 20:50:57

Bob

I've spent 30 minutes trying to make this work; finally resorting to the Imgur help site.  They say bcc codes are only available on desktop devices.     So sorry sad

From the internet chat surrounding this difficulty there are lots of unhappy image posters out there.

You can get the https adress of your image like this:

Log in to Imgur.

Click the person icon (bottom right on my screen) and your images appear.

Select the one you want and click the right arrow.

Click copy url.

Log in to the forum and start a post.

On the text input screen press and hold to get the paste option.

This will give you something like this:

https://imgur.com/a/BURsC8w

This track car picture was needed when I was helping a guy with his car frame geometry.

Anyone can copy and paste this into a fresh browser tab to view your image.

NOTE TO OTHER MEMBERS: Can anyone recommend a good image hosting site that does support bcc codes when using a mobile.

Bob

#22 Re: Help Me ! » Solve for a: Reviewing the Basics » 2022-09-22 22:02:32

Bob

hi harpazo1965

Generally any solution is acceptable.  Many years ago I did some Advance Level marking for the UK EdExcel exam board.  There was one question that specified the method to be used and the chief examiner said any candidate who used another method should get no marks!  That is very unusual.

I would have used the same method as you but written less steps:

30 = 26 - (a/6)

(times by 6)

180 = 156 - a

(re-arrange)

a = 156 - 180 = -24

which is just 3 lines, same as Ganesh.

This equation is 'linear' meaning if you plot the graph y = 26 - a/6 you get a straight line.  The line y = 30 will cross it in just one place, so there is exactly one solution.  Sometimes you may spot a solution 'by inspection'.  It is acceptable to state this and then show it works:

I notice that -24 looks like a solution.

check 26 - (-24/6) - 26 + 4 = 30.  As this equation is linear this is the solution.  That's a two line answer smile

Bob

#24 Re: Help Me ! » Write In Standard Form » 2022-09-21 03:18:31

Bob

If the question asks for standard form then that's what is expected.  Half the question is the working out; the other half is having the answer in sf.  No getting away from it I'm afraid.

B

#25 Re: Help Me ! » Write In Standard Form » 2022-09-21 00:54:25

Bob

hi harpazo1965

See https://www.bbc.co.uk/bitesize/guides/z … revision/1

Your arithmetic is correct but it is best to leave the powers of ten if you want to end up with standard (index) form.

So a number between 1 and 10 followed by a power of ten.

Back in the days before calculators logarithm tables were often used to do calculations.  A table book usually had the logs of numbers between 1 and 10 so having numbers in stardard form made this easier.

eg.  In base ten log 2 ≈ 0.3010 ; log 20 = 1.3010 ; log 200 ≈ 2.3010 ; log 0.2 ≈ -1 + 0.3010 ; log 0.02 ≈ -2 + 0.3010 etc.

Page 6 of that BBC bitesize shows a calculation using standard form and page 7 shows how a calculator displays numbers that are too big |(or small) to fit the screen size.

Bob

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