Melody

You haven't actually asked a question but Alan has expanded and simplified your expression.

Our anonymous guest made a little error.  But I like to see people 'having a go' so thankyou.

$$y=2x^2+5x\\
\mbox{ It is a concave up parabola because the coeffeicient of } x^2 \mbox{ is positive}\\
y=x(2x+5)\\$$

When y=0 x=0 or x=-5/2 

So the roots are x=0 and x=-5/2

The axis of symmetry is the average of the 2 roots x=-5/4

When x=-5/4

$$y=2\times\frac{25}{16}+5\times\frac{-5}{4}\\\\
y=\frac{25}{8}+\frac{-25}{4}\\\\
y=\frac{25}{8}+\frac{-50}8}\\\\
y=\frac{-25}{8}\\\\
\mbox{ therefore}\\\\
\mbox{Vertex is }\left(-1\frac{1}{4},-3\frac{1}{8}\right)$$

Just as CPhill said.    

Thanks for answering CreeperCosmo but I do believe you have made a small mistake.

Since you are a member you can edit your answer and fix it. 

-----------------

This question could also be interpreted differently. It could be;

$$2x+\frac{1}{3}-2=-7\\
\mbox{ or}\\
\frac{2x+1}{3}-2=-7\\$$

Maybe the asker could tell us which was required.

The motto is - Always use brackets, even when using words!

Thanks Alan

I just thought that i would point out that this does not have to be base e.  It can be base 10 or base whatever you want.  Calculators only deal with base e and base 10 so you had best use one of those. 

Sacha, if you have any problem understanding what Alan has done make sure your ask for clarification.  We all love to get polite feedback. (positive, negative or queries)

x is in the 2nd or 3rd quadrant

sinx is positive so x is in the second quadrant.

x=pi-(pi/6)=5pi/6

so x/2 = 5pi/12

80/200*100% = 40%

4x² can not be simplified

but

(4x)² = 4²x² = 16x²

so it depends on what you actually intended your question to be. 

No.

If you have a function y=f(x)

then the domain is the set of all possible x values.

The range is the set of all possible y values

and I have no idea what the first element is.

Maybe my wording isn't quite right but the meaning is correct.

I have drawn the graph so that you can 'see' what Alan is telling you.

We can't insert attachments at the moment so I have placed the graph at the following address.

Hi all,

There have been a LOT of questions.  All member questions have been answered.  Most, but not all, of the anonymous questions have been answered - there simply has not been enough time to answer all.  Members must get priority.  It is easy to join up and priority answering is one of the benefits. 

Great answers were given by BlindxD, CPhill, reinout-g, Alan and CreeperCosmo.  Thank you all.  I hope I haven't left anyone out.

Old inbox messages have now been restored; thank you Andre.  Old outbox messages are not restored yet and there is no way to delete messages. I have received many messages and I have responded to very few.  The messages that I have sent are not displayed to me (because there is no outbox) so I am not keen to contact people this way.  I would prefer it if people continue to use my personal email address to contact me.  I will add the address at the end of this post.  

It is now possible to very easily search another member’s posts.  But I think this has to be done by clicking on the username.  I don't think that you can actually type a username anywhere to bring it up.  I might be wrong, I am feeling my way the same as everyone else.

Answerer names are now included on the 'questions' tab page and the 'answers' page. This is great. Thank you Andre.  

I think Andre Massow has been experimenting with the second tab 'Answers Page'.  This page is not working for me.  I would really like it to be displayed much more like it was before the forum got its new look.  Today I found a response from a question that was first entered a few days ago.  It is only lucky that I saw it.  I would like one of the display tabs to be questions sorted on most recent post.   To the best of my knowledge, this is what other primary answerers want as well.  If anyone would like to expand or comment on this maybe you could post a @@message in the main forum.  Andre and I do NEED your feedback.  I hope you are reading this Andre. Maybe I shouldn't have mentioned this yet, I know that Andre is already fully occupied with higher priority issues. It is written now so I will leave it - I would like the opinion's of other members anyway.

Tonight BlindxD posted a question which Alan answered.  The question became interactive with Blindxd asking for clarification.  Thank you BlindxD, this is what we want in the forum.  Ask lots of questions and never 'pretend' to understand.

There were a number of fun and chatty posts today.  I think that this is great.  I do not want the forum to be too serious.  The 'I like Turtles' post turned into a fun little thread and I also rather liked this thread.   

That is it I think, Enjoy what is left of your Tuesday.

Melody.

melodymathforum@gmail.com