MATHS: Integration

[Luckeh!!!!]

Integral of (cos(x))^4

or (cosine of x) to the 4th whichever, anyone have an idea?

I think i did this question a bit wrongly anyway...

[BeeKiller]

yeah i believe u treat it as ((cos (x)) ^2 ) ^2
i aint done a lvl maths for about a year, but i think u either use a double angle formula for (cos (x) ^2) or something along those lines, or maybe u have an identiy for the integral of cos(x)^2 ?
if so it'd simply be 1/3 * (integral of cos(x) ^2) ^ 3 i believe. Edit: + C

[queball]

http://integrals.wolfram.com/
tap in Cos[x]^4
You can do it just using trig identities and that the integral of cos is sin. You might be expected to use integration by parts and an iteration formula instead depending on the question but if not don't worry about it.

[Luckeh!!!!]

nah... I think i done the question wrong then, the answer needs to be something simple.

http://www.starlance.freeserve.co.uk/pics/p1.bmp
http://www.starlance.freeserve.co.uk/pics/p2.bmp

[Nodrog]

Originally Posted by Luckeh!!!!

nah... I think i done the question wrong then, the answer needs to be something simple.

http://www.starlance.freeserve.co.uk/pics/p1.bmp
http://www.starlance.freeserve.co.uk/pics/p2.bmp

The answer isnt simple, it's that (you need to enter it in the exact syntax queball used).

[MrL_JaKiri]

Originally Posted by queball

You might be expected to use integration by parts and an iteration formula instead depending on the question but if not don't worry about it.

It looks to be P5 to me, so qbll is correct in that you need to use an iteration formula.

[Radical Edward]

I hate cosines, convert them into exponentials and then bring it back.

[acropolis]

cos^2 = 0.5(1+cos 2x)

0.25(1 + 2 cos 2x + cos^2 2x)

0.25(1 + 2 cos 2x + 0.5(1+cos 4x))

rit?

int of cos 2x and cos 4x are both pretty easy.

[Luckeh!!!!]

my workings is incorrect, so I don't get (cos(x))^4, thnx all