Maths

[robinitnow]

Douse anyone know what the integral of 2xsinx is? Please help me!

[naimex]

2 times the SinusX ^^ is that the Cosinus ?? =/ if only I had paid attention during school ^^

I really dunno.. but thats a helluh [OT] Thread ^^

[Shujin]

is it 2(x)sin(x) ?

[naimex]

^^ thats how i read it.. but dunno what it is.. ^^ unless its Cos(x)

[robinitnow]

x is an x not a times

I think the answer is sinx-2xcosx but I don't really know

[Shujin]

bah i was thinkin x as variable.... which x(s) are variables?(leaving thread cuz its makin my brain twitch)

edit: if its times, then put * ;/

[robinitnow]

chears for the help anyway

[Owain]

You use parts for this problem

2(x)Sin(x)

u=sin(x) dv=2x
du=-cos(x) v=2

that should start you off on it


Edit:

int (f(x))(g(x))dx = f int (g dx) - int (df(int (g dx)) dx)


f(x) = 2(x)
g(x) = sin(x)


The answer you had up there is close but you are missing a 2

int (2xSinx) = 2(Sinx - xCosx)

[FuzzyDuck]

OMG. I've just started this integrating stuff in school. All I can do is things like;

find the integral of f(x) = x^4 + 2x^3 - x^1/2



*dies*

[Owain]

Originally posted by FuzzyDuck
OMG. I've just started this integrating stuff in school. All I can do is things like;

find the integral of f(x) = x^4 + 2x^3 - x^1/2



*dies*

(1/5)x^5 + (1/2) x^4 + (2/3)x^(3/2)

[Richard Slade]

I'm still working on the damn
(X-2)+3X*(19/32)-5^2
o_O

[FuzzyDuck]

Originally posted by Owain
(1/5)x^5 + (1/2) x^4 + (2/3)x^(3/2)


I hate computer notation, I prefer good ol' pen and paper :p. How long before I'll start doing that stuff with sine and cosine and stuff?

(currently in lower 6th)

EDIT > Spelling

[Owain]

I was working on

y' + y(sinx) = arctan(x)y^3; y(0) = 0, solve for y

a few months ago.

I'm not into matrixies, plural of matrix, and n-space vectors; using calculus of course.

@Fuzzy

You will get some of that in Gemotry(sp?), but you'll get most of your trigonomotry training in Trig/Pre-Calc. Which is taken in highschool and it depends on how far in math you get to in middle school.