Maths Problem Thread!!

DarkDusk

Ok, I thought of an idea. Post you problem here and see if someone can solve it. When someone else solves it, they can post a question. And so on....
I'll start it off:
f(x) = 2x +1, for x ∈R.
Show that there exists a real number k such that for all x,
f(x + f (x)) = kf(x).

So get your thinking-cap on! lol

partyatmygaff

f(x) = 2x + 1
f(x + f(x)) = 2(x+2x+1) + 1 = 6x + 3

Therefore k = 3

Here's my question (It's a tough one)

Integrate the following (Indefinite)

[LATEX]\int\! x^2Sin(x) \, \mathrm{d}x[/LATEX]

eoins23456

http://www.wolframalpha.com/input/?i=x^2*sin(x)

partyatmygaff

eoins23456 wrote: »

http://www.wolframalpha.com/input/?i=x^2*sin(x)

You won't have WolframAlpha with you in the exam...

jumpguy

partyatmygaff wrote: »

f(x) = 2x + 1
f(x + f(x)) = 2(x+2x+1) + 1 = 6x + 3

Therefore k = 3

Here's my question (It's a tough one)

Integrate the following (Indefinite)

[LATEX]\int\! x^2Sin(x) \, \mathrm{d}x[/LATEX]

Is that not integration by parts, no?

Will need the ole pen and paper for that job...

partyatmygaff

It is... I'll say no more