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#1 2013-03-08 08:14:55
- Al-Allo
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Algebra -Subject
Hi
s = ut +½at^2
So I want you to tell me why my way of doing is wrong : (a must be the subject)
-ut s = ut +½at^2 -ut
/ ½t^2 s-ut=½a^t2 / ½t^2 (This is how I think I should have done it, because we want only the a, so you divide all in one shot)
s-ut/ ½t^2=a ===> a=s-ut/ ½t^2
I Know this is the wrong answer, but explain me why my way of doing is wrong, because I have no idea why ! Thanks
#2 2013-03-08 08:27:04
- bobbym
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Re: Algebra -Subject
Hi;
Is this the question?
You want to solve for a?
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#3 2013-03-08 08:29:58
- Al-Allo
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Re: Algebra -Subject
I want 'a' to be the subject of the formula, I already did my way of doing, which is wrong, and would like to know wy it's wrong. Thanks
#4 2013-03-08 08:33:16
- bobbym
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Re: Algebra -Subject
Hi;
Just trying to get the exact question. You want a on the left by itself and that is the correct form in post #2.
This is the answer.
Last edited by bobbym (2013-03-08 08:36:09)
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#5 2013-03-08 08:37:05
- Al-Allo
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Re: Algebra -Subject
Yes, that's what I want, 'a' on the left of the formula.
#6 2013-03-08 08:43:02
- bobbym
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Re: Algebra -Subject
Hi;
Times everything by 2
Subtract 2ut from both sides
Divide by t^2.
Clean up.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#7 2013-03-08 08:47:20
- Al-Allo
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Re: Algebra -Subject
Oh wow.....It's clear now ! I understand now ^^ thanks. The way you present the formula is more clean, I got misleaded by my mess lol
#8 2013-03-08 08:50:06
- bobbym
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Re: Algebra -Subject
Hi;
Just remember I treated it algebraically. Like a bunch of letters. t must never be zero.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#9 2013-03-08 09:08:11
- Al-Allo
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Re: Algebra -Subject
Ok, by curiosity, do you know where I could practice more of these ?
#10 2013-03-08 09:09:14
- bobbym
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Re: Algebra -Subject
I could give you a few if you want or I will look up a page if there is one.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#11 2013-03-08 09:13:50
- Al-Allo
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Re: Algebra -Subject
That would be great, always looking to practice 
Anyway, I need to go
! BYe
#12 2013-03-08 09:18:17
- bobbym
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Re: Algebra -Subject
Okay, here are three.
Make a the subject.
Or
Make b the subject.
And last!
Make b the subject.
Last edited by bobbym (2013-03-08 09:34:30)
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#13 2013-03-09 04:23:16
- Al-Allo
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Re: Algebra -Subject
i did the first one
a=s-ut^2
btw, do you have an article on these ? im having a hard time doing these ^^ ty
a(x)a-x/-2=b
b=1/u.a
Last edited by Al-Allo (2013-03-09 04:33:59)
#14 2013-03-09 12:26:21
- bobbym
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Re: Algebra -Subject
I made them up for you.
You should get
Last edited by bobbym (2013-03-09 12:26:48)
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#15 2013-03-09 15:45:36
- Al-Allo
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Re: Algebra -Subject
Oh man, I don't know why but I'm having trouble with these. I dont know where to begin and always get a different answer >.< And what I meant by article is something that tells how to approach rearranging formulas
#16 2013-03-09 19:09:17
- bobbym
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Re: Algebra -Subject
Hi;
Follow along with what I do:
Subtract u from both sides.
Clean the denominator on the right, t*a*t^2 = a*t^3.
Multiply both sides by a
Divide both sides by (s - u)
Last edited by bobbym (2013-03-09 19:22:11)
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#18 2013-03-10 04:32:23
- anonimnystefy
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Re: Algebra -Subject
Hi Al-Allo
You should have a on the left hand side. And the expression you got that isn't correct either.
The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“A secret's worth depends on the people from whom it must be kept.” ― Carlos Ruiz Zafón
#19 2013-03-10 04:32:45
- bobbym
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Re: Algebra -Subject
Hi;
That is not correct. What was your first step?
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#20 2013-03-10 04:38:11
- Al-Allo
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Re: Algebra -Subject
here is what I did : (like I said, Im not sure how to begin these, to many steps, but the simple ones I can easily do them)
*bu 1/a=1/b+1/u *bu
*a 1/a *bu= 2 *a
bu/2=2a/2
a=bu/2
Last edited by Al-Allo (2013-03-10 04:38:31)
#21 2013-03-10 04:42:21
- bobbym
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Re: Algebra -Subject
Hi;
Okay, let's follow your idea and times both sides by bu.
You should get:
Last edited by bobbym (2013-03-10 04:42:39)
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#22 2013-03-10 04:44:39
- Al-Allo
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Re: Algebra -Subject
OKay, but isn't it supposed to be 1+1 on the right side ?...
#23 2013-03-10 04:49:08
- bobbym
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Re: Algebra -Subject
Hi;
No, you are cancelling too much. let's see what happens just on the left.
Now cancel the b in the first fraction.
Are you okay up to here?
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.
#24 2013-03-10 04:51:29
- Al-Allo
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Re: Algebra -Subject
AHHHHHHHHHH... okay that why. Mh bobbym, could we continue later this way of doing ? Because I need to go like now. We shall continue later, when I'm online ? Thanks for your help
#25 2013-03-10 04:59:18
- bobbym
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Re: Algebra -Subject
Okay, I will see you later. Have a good day.
In mathematics, you don't understand things. You just get used to them.
Probability is the most important concept in modern science, especially as nobody has the slightest notion what it means.
90% of mathematicians do not understand 90% of currently published mathematics.