A maths Q. (1 Viewer)

[Iheartpaulfrank]

this is a really dumb question but...

how do u integrate xe<SUP>x ? what is the answer?</SUP>
<SUP></SUP>
<SUP>damn got myself stuck on superscript....<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o></SUP>

 

[pLuvia]

You'll have to use Integration by Parts, a 4 unit method. Unless the integral was xe^x2 then you could do it.

But if you want the answer
xe^x-e^x+C

 

[Forbidden.]

When do we learn Integration and stuff like that ?

And what on earth is the "e" notation ?

 

[B35tY]

You're in year 11, right? HSC: 2007.

You'll learn it next year, it's not as hard as it seems. Basically, integration is the opposite of differentiation and "e" is just a number.

 

[pLuvia]

Integration you should learn when you start year 12. e stands for exponential, you know those exponential graphs you draw? It's that. e=2.71828..

 

[Forbidden.]

Integration you should learn when you start year 12. e stands for exponential, you know those exponential graphs you draw? It's that. e=2.71828..

y=e^x ? Yeah, but that alone does't help that much ...

 

[ane_st]

dude you'll learn it next year... Why would you care now?

 

[pLuvia]

Integration is finding the area under a curve, or the volume of a curve under certain applied limits. So for int. e^x, you are finding the area under that curve

 

[Forbidden.]

dude you'll learn it next year... Why would you care now?

Because Mathematics, not to mention Extension 1 ... Has become exponentially difficult, from "Write 0.2 in percentage form" in the beginning of the year to where we will get crap I heard is intergration and simpsons rule .... I wished I did General Maths ...

 

[jemsta]

have you considered tutoring?
im sure if you really care about your marks that you'll consider tutoring because seriously....that saved my ass

 

[Forbidden.]

have you considered tutoring?
im sure if you really care about your marks that you'll consider tutoring because seriously....that saved my ass

Mathemagic Computer Tutor from the Australian Institute of Mathematics ...

 

[jemsta]

haha well i didnt use mathemagic computer tutor.....went to a tutoring college but you can try it if you want.....

 

[acmilan]

Integration you should learn when you start year 12. e stands for exponential, you know those exponential graphs you draw? It's that. e=2.71828..

Actually, e is Euler's number. It just happens that that e^x is a solution to exponential decay/growth problems.

 

[Iheartpaulfrank]

actually here's the real question... (woops)

Use Simpson's rule with 3 function values to find an approximation to

∫xe<SUP>x </SUP>dx, correct to 1 decimal place.

p.s the values beside the integral are 1 to 2 (i don't know how to place numbers beside the integral thingy)

please show working out!
thanks!

 

[Slidey]

Actually, e is Euler's number. It just happens that that e^x is a solution to exponential decay/growth problems.

Yes, but e is many things. It's a special value like pi because it doesn't represent an IDEA (such as that 0!=1) but rather a quantity that often pops up and is inextricably interwoven into the fabric of mathematics. For example, you could take what you just said and invert it, and it would still be true. So I think that what pLuvia said, whilst not as formal, is equally as true.

One definition of e is that it is a number such that when raised to the power of x, the derivative of this expression is itself. It turns out there is only one unique value of that number: 2.718 blah blah. In maths: y=r^x. y'=ln(r).r^x. Obviously you can see that if r=e, then y'=r^x=y.