Why learn algebra?

JessopSmythe

Active Member
You can use algebra to prove or disprove allsorts of theories. eg:

Given that a=b,
then a²=ab
also, a²-b²=ab-b²
and (a+b)(a-b)=b(a-b)
therefore, (a+b)=b
or (a+a)=a
or, more simply, 2a=a
which means that 2=1 :?
 

Jo Elson

Member
And the point is.... there isn't one to doing algebra.
I hated learning algebra and pythagoras's theorum, wot a load of monotonous rubbish. We used to have questions where you'd have a trianlge but only two of the sides lengths were given and you had to find t'other out, by knowing that the hypotenuse always equaled the other two or somethin
A(2)=B(2)+C(2)
 
It's easy as he.. But vector arithmetication (dunno if it's called that in english) is 20x harder than algebra... Btw. pythagoras theorem says a^2+b^2=c^2
 

johnmartin

Active Member
JessopSmythe said:
You can use algebra to prove or disprove allsorts of theories. eg:

Given that a=b,
then a²=ab
also, a²-b²=ab-b²
and (a+b)(a-b)=b(a-b)
therefore, (a+b)=b
or (a+a)=a
or, more simply, 2a=a
which means that 2=1 :?
except that (a-b)=0 meaning that you are dividing by zero to get the fourth line in your theorem. Division by zero would result in an undefined answer so the rest of your theorem falls down on this step.
 
Algebra is good fun - it was always my favourite subject at school.
It comes in handy for solving puzzles.
Do you need any other reasons for learning it
 

BigHorn

Active Member
Jo Elson said:
And the point is.... there isn't one to doing algebra.
I hated learning algebra and pythagoras's theorum, wot a load of monotonous rubbish. We used to have questions where you'd have a trianlge but only two of the sides lengths were given and you had to find t'other out, by knowing that the hypotenuse always equaled the other two or somethin
A(2)=B(2)+C(2)
I always loved algebra - probably because we had a good, entertaining maths teacher who always explained why it was useful in a practical sense. He always used to tell us the story about the Red Indian chief 'Python in the grass' who had three wives. Two of his wives sat on buffalo skin whilst his favourite wife, who he liked as much as the other two put together, sat on Hippo skin imported from Africa.
i.e.
The squaw on the hippopotumus is equal to the sum of the squaws on the other two hides.
 

Jo Elson

Member
We were told Maths is like an onion because its got so many layers-which still makes us laugh and the fact that he used to put this one lad in her office and shut the door so he'd send suicide notes under the door to her, or if she sent him out he'd take the screws out the handle so it fell off-oh those were the days.
 

bruceg

Active Member
JessopSmythe said:
You can use algebra to prove or disprove allsorts of theories. eg:

Given that a=b,
then a²=ab
also, a²-b²=ab-b²
and (a+b)(a-b)=b(a-b)
therefore, (a+b)=b
or (a+a)=a
or, more simply, 2a=a
which means that 2=1 :?
Hmmm... As with most theories there are defined ranges for when they hold true. In this case it's only true for a=b=0 and no other value.

John reckoned it fell down at stage 4 but I think it's ok to manipulate the equations until the point of substituting values for the variables...

Oh oh - self declared BOC alert :D
 

bruceg

Active Member
BigHorn said:
I always loved algebra - probably because we had a good, entertaining maths teacher who always explained why it was useful in a practical sense. He always used to tell us the story about the Red Indian chief 'Python in the grass' who had three wives. Two of his wives sat on buffalo skin whilst his favourite wife, who he liked as much as the other two put together, sat on Hippo skin imported from Africa.
i.e.
The squaw on the hippopotumus is equal to the sum of the squaws on the other two hides.
:D :D :D
 

ScrapingtheBottom

Active Member
I think the biggest nightmare out there is either Statistical Mechanics or Fluid Mechanics, but Complex non-linear algebra runs them close.
 

Keppler

Moderator
Staff member
aaah Fourier Transforms...
The basis of the Kepps/Bighorn Adjud-O-Matic...
Have you built it yet, BH?
 

MoominDave

Well-Known Member
bruceg said:
JessopSmythe said:
You can use algebra to prove or disprove allsorts of theories. eg:

Given that a=b,
then a²=ab
also, a²-b²=ab-b²
and (a+b)(a-b)=b(a-b)
therefore, (a+b)=b
or (a+a)=a
or, more simply, 2a=a
which means that 2=1 :?
Hmmm... As with most theories there are defined ranges for when they hold true. In this case it's only true for a=b=0 and no other value.

John reckoned it fell down at stage 4 but I think it's ok to manipulate the equations until the point of substituting values for the variables...
No, don't think so - you're still dividing by 0, as 0 - 0 = 0. By the initial assumption (a=b, so a-b=0, independent of chosen values), John is right.

ScrapingtheBottom said:
I think the biggest nightmare out there is either Statistical Mechanics or Fluid Mechanics
Then I shouldn't go anywhere near Magnetohydrodynamics (which incorporates the standard treatment of magnetically confined plasmas). It doth rot the brain...

Do I win the "How abstruse and obscure an Applied Mathematical concept can I casually mention to make myself look clever?" contest? :lol:

Dave
 
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