am i just plain stupid?

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also one more question.
do i wrote domain like this [-2,2]
or do i say -2<x<2? the book has the latter but im used to the formers.
 
Either are fine, but the equivilant to [-2,2] is -2 <= x <= 2.

"]" means "includes"
")" means "up to but excluding"
 
yeah, ill just write it with the parenthesis/brackets. yeah im good with that i just didnt know how to make the line under the < on this site.
does anyone know the other questions i asked id really like to know before my quiz tomorrow. i went to get tutored today but she was all booked so i couldnt ask a lot of questions.
 
If f(x)=3, this is saying for any input x, the output is 3. So even if x=pi*sqrt(3)i^(-17/6), the answer would be f(x)=3. This is called a "constant function" because the output never changes.


Please explain the second and third problems a little more. Please be clear on what information is GIVEN, and what is asked to be FOUND. If necessary, state what must be done in order to obtain the solution and where you are having difficulty.

For example:

GIVEN x is an integer contained in [-3,3] and y=5x-2, FIND the outputs y for each x. The answer would be {-17, -12, -7, -2, 3, 8, 13}.

edit:

If you plan to use online message boards for math help, you might want to learn at least the basics of LaTeX. Quote my post to see how I did the following:

\(\displaystyle x \le y < 3\)

\(\displaystyle x \ge y > 7\)

\(\displaystyle \frac{x}{y}\)

\(\displaystyle 2^{\sqrt[\pi]{y}} = x^{3\sqrt{2}}\)

\(\displaystyle {m-2} \choose {n+1}\)

\(\displaystyle y = 3 \frac{ -\sqrt{x} }{2^x}\)

\(\displaystyle y \ge \pi \sqrt[3]{\frac{1}{2}x^{\sqrt{2}}+\sqrt[4]{x+7}}\)
 
sportsstar469 said:
o ok thanks a lot, so as long as i divide it out it shouldnt matter im guessing?
what exactly do you mean its a convention
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A convention - a habitual way that things are expressed...

Some of the more well-known conventions in math are that the symbol '2' means the number after 1, that 8-3 means 'take 3 away from 8' rather than the other way round or some other operation, and so forth.

Historically, decimals were introduced as a shorthand way to write certain fractions... 7.3 meant "7, and 3 tenths". In this sense,

\(\displaystyle \frac{7.2}{5.3}\ {\mathrm{means}}\ \frac{7\frac{2}{10}}{5\frac{3}{10}}\)

which is clearly more complicated than

\(\displaystyle \frac{72}{53}\)

Or, if you are going to use decimals anyway, why not go the whole way and write the answer as 1.35849057.... ? :)
 
Subhotosh Khan said:
Learning mathematics is very boring - just like learning another language (the grammar, the idioms, the jargons -- exactly the same littany of painful demands). Obviously it will take very hard work and diligence (I am sure you know that). My grandfather used to say -
Code: 
Only way to learn mathematics is, to do hundred problems 

                 - if that does not work, do 500 problems 

                                            - it will work.
Click to expand...

“There is a strong family resemblance about misdeeds, and if you have all the details of a thousand at your finger ends, it is odd if you can’t unravel the thousand and first.”
Sherlock Holmes – A Study in Scarlet

They say that inspiration is but a momentary cessation of stupidity.
In your case (or anyone for that matter), once you’ve been exposed to (or seen, worked out, or gone through) the solution formats of a thousand math problems, I’m betting (statistically anyway) that you will (or must) eventually wake up from your self-declared delusion of stupidity (or ignorance).

Consider the folllowing:

SOME BITS AND TIPS ON TEACHING MATHEMATICS

49’ Most mathematics problems can be solved with ordinary talent accompanied by extraordinary perseverance.

32’ Nothing in problem solving can take the place of perseverance – talent alone will not, genius alone will not, education alone will not. It is perseverance that finally solves most problems. The slogan “press on” has solved and will solve many a mathematical problem. In other words, stayabilityy is more important than ability.

31’ The secret of success in problem solving can be stated in nine words: Stick to it,, Stick to it, Stick to it.

On a lighter note, I’ve been told there’s something about being evil that jacks up the I.Q. Personally, I’m really “evil” and unusually happy when I’ve had a little something to drink when pondering a math problem. I suppose the resulting “numbness” I get from the drink helps in keeping me focused. It certainly drowns out most minor considerations, irritations (like an itchy butt for example) and distractions. I simply don’t mind anything at all when I’m drunk contemplating a math problem.

Remember: It’s all right to operate a calculator or a computer while drunk. But never ever drive or fly an airline jet (remember those two airline pilots who figured in the news years ago for flying intoxicated?), nor ever operate (when you’re already a doctor) under the influence of alcohol.
 
..we(hic!)ll occifer, I ha(hic!)ve to driiiiiive, I'm to(hic!)o druuuuunk to waaaaalk !
 
. Mathematics isn't boring , I'm addicted to MAth. :wink:

Jonah, thumb up .
 
Whomever says math is boring does not appreciate it for the grand thing it is. They look on it as a punishment they are made to endure in school instead of
opening their minds.

Most folks would rather freight an iron stove up a mountain than have to work their brain at all.

They are afraid to use their heads for anything other than something on which to grow hair.

But, I digress. We all have our interests and things we can't stand. Me, I do not like sports of any kind.

That is something I find boring and do not understand the fascination at all.

Let's turn on the TV and see who is doing what with what ball today. Unless, of course, it has to do with the physics or
math involved with it.
 
hey guys just thought id update you. i think i did OK on the last quiz we had. i choked when she gave it out and almost threw up and left the room but i pulled it together and think i got a 90 or so. i think i might have not read the whole question though, because iremember her saying their would be itnerval notation problems but i never saw them oh well.

ANYWAY i have another question that i really need help on. the teacher never really tought us absolute value problems because its a fast paced course so im a little confused on why the answer to this problem is no solution. im not sure how to make abs value signs so ill just write abs of.

PROBLEM- solve this abs value eq. symbollically give each answer as a set (book says the answer is no solutions)

|5x-9|+3=1
ok first i subtract 3 to both sides to get |5x-9|=-2
then i make 2 equations of |5x-9|=2 and |5x-9|= -2
i subtract 9 from both sides respectably and get {7/5,11/5}
i then plug both of these points into the original equations and i do indeed get -2 and positive 2, so what the heck how is it no solution!!!
im feeling so discouraged!!!!
 
abs of a number means dropping the minus sign IF there is one;
abs(9) = 9; abs(-9) = 9

|5x-9|+3=1 ; |5x - 9| is simply another way of showing abs(5x - 9).
Since |5x - 9| is always positive, then no solution since -2 + 3 = 1
 
idk im still confused on that one since the solutions worked and in the book it has one where it equals a -5 and it still works.
im getting bvery frustrated about my carlessness though. i am not as stupid as i thought. i just tought myself abs value equations to a degree, and i tought myself how to substitution and elimination of systems IN 3 VARIABLES. however i got the systems of three variables problem wrong because when clearing out ys from x-y+2z=6 and -x-2y+3z=7 i multiplied the first equation by negative 2, AND I ONLY MULTIPLIED THE 6 BY NEGATIVE 1. so after all the algebra i got the wrong answer. if this was a test i wouldnt have known that. but since i have the answers i do know. itd be a bummer to fail this course even though i understand the material!!!!!!!!!
(i now someone might say i didnt have to clear out the ys since the xs weree already cleared but i already found x from the previous 2 equations so i needed to find y so i could plug both into the original to get z.

i gotta tell you though im pretty proud of myself that iwas able to teach myself this. i know its easy math to you guys but still.
 
sportsstar469 said:
You should start a new thread (new topic with new problem

PROBLEM- solve this abs value eq. symbollically give each answer as a set (book says the answer is no solutions)

|5x-9|+3=1
ok first i subtract 3 to both sides to get |5x-9|=-2 <<< By DEFINITION - absolute value is ALWAYS positive. End of story.

There is NO SOLUTION - because you are asking an ABSOLUTE VALUE to be negative.
Click to expand...
 
iudk i think for that one ill jsut ask the tutor because ineed to show her a problem in the book that looks like its negative to be and resulting in an absolute value.

so im supposed to start a new thread for every new question i have? i figured that would be spamming the board since im coming up with a lot of new question as i go through my homework i figured youd guys would prefer if i kept my questions in one thread. im kind of offended that this thread got moved to the jokes section i dont think my help is a joke ha.
if yo uguys would prefer a new thread every time i have no problem with that just let me know if that what youd like as i think im misunderstanding you. i think its more logical that you guys would want this all condensed to just one condensed thread.

with that being said i have one mroe question LOL. i will include it in a new post after this reply so it doesnt get confusing hehehe.
 
can all systems of equations word problems be solved by using a quantity values table? im pretty good at using q times v tables and not as good with pulling the equations out mauallys.

here is my problem f it is not to much trouble can you guys help me figure this out

an airplane takes 3 hours to travel a distance of 2160 miles with the wind. The return trip takes 4 hours against the wind. find the speed of the plane in still air and the speed of the wind.
 
Let \(\displaystyle r_{p}=\text{rate of plane}, \;\ r_{w}=\text{rate of wind}\)

When the plane is flying with the wind, it's rate is \(\displaystyle r_{p}+r_{w}\).

When it flies against the wind, its rate is \(\displaystyle r_{p}-r_{w}\)

Now, use the formula d=rt to solve. You have two equations with two unknowns, \(\displaystyle r_{w} \;\ \text{and} \;\ r_{p}\)
 
thanks yeah. i know that x+y and x-y are the 2 equations im just not sure what is after the equals sign. does that equal the distance or the time? im guessing the correct equations are

x+y=3 with the wind
x-y=4 without the wind

now i dont really remeber anything about distance ihonestly was never good with distance and dont think istudied it too much last semester.

distance equals rate times tiem w/e that means. so if my distance is 2160 then i get...

x+y= 3 (2160)
x+y=4(2160)

which gives me
x+y=6480
x+y=8640

now im lost at where to go from here since if i multiple by a negative one to the top equation, both the x's and the ys will cancel out and i only know what to do if one of the variables cancels out. (i did solve a 3 varialbe system where they both canceled out but i was sort of confused and made a carless errors.
 
wow they set it up like a q times v table im gonna look at it later. all this math is making me hungry but that looks like itll be very easy to understand. for now ill devour my subway but when i get home ill devour problem two since you think itll be the most beneficail kind for me anyways time for me to east a tasty sub.
if it takes me 15 minutes to get to the subway and 3 minutes to order, and and then another 15 minutes to get home, and 30 seconds to eat it.
how long before the subway diarrehea ensues =p
haha.
 
sportsstar469 said:
an airplane takes 3 hours to travel a distance of 2160 miles with the wind. The return trip takes 4 hours against the wind. find the speed of the plane in still air and the speed of the wind.
Click to expand...
C'mon SStar, slow down; you're complicating something real easy;
the net speeds are this easy to get:
with wind: 2160 / 3 = 720 mph ; so plane's real speed is slower than that
against wind: 2160 / 4 = 540 mph ; so plane's real speed is faster than that...get my drift?
 
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