Need Help With an Integral

2008-11-02 16:27:25

#1

mtb0minime: minimember; +2,418|7104

Boy it's been a long time since I did some of this stuff. This is really easy and I know I should know it, but can't help but think I'm missing something.

https://img355.imageshack.us/img355/3788/41789838mk4.jpg

N₀ is a constant and so is c. I just need to get that equation in terms of N₀ and c.

I want to do integration by parts (int. u dv = u*v - int. v*du) but I'm not sure if that's correct.

Thanks in advance and any help is greatly appreciated!

2008-11-02 16:44:42

#2

CammRobb: Banned; +1,510|6580|Carnoustie MASSIF

=wat?

2008-11-02 16:57:29

#3

mkxiii: online bf2s mek evasion; +509|6686|Uk

what is the equivalent of x that will be taking the definite boundaries between 0 and infinite?

2008-11-02 16:58:06

#4

mtb0minime: minimember; +2,418|7104

1n_n07h1ng_w3_7ru57 wrote:
=wat?

= Z; reflectivity factor of raindrops measured by RADAR

2008-11-02 16:59:20

#5

mtb0minime: minimember; +2,418|7104

mkxiii wrote:
what is the equivalent of x that will be taking the definite boundaries between 0 and infinite?

"D", hence the dD at the end

If you do manage to figure this out, hopefully it'll match mine, as I think my original assumption of using integration by parts will work.

2008-11-02 17:15:21

#6

mtb0minime: minimember; +2,418|7104

Ok, fuck this. It's not working and I have no idea what else to do.

Couple years ago I could've done this, but it's been forever since I did anything other than extremely basic calculus (and this is only slightly more than basic calculus, so it's really frustrating because I should know this shit )

Last edited by mtb0minime (2008-11-02 17:15:51)

2008-11-02 17:18:35

#7

CammRobb: Banned; +1,510|6580|Carnoustie MASSIF

What are you studying?

2008-11-02 17:22:26

#8

mtb0minime: minimember; +2,418|7104

Introduction to Environmental Engineering.

We're learning how to predict precipitation based on results from a RADAR station.

2008-11-02 17:24:19

#9

CammRobb: Banned; +1,510|6580|Carnoustie MASSIF

How the hell does that mean rain?

2008-11-02 17:28:20

#10

mtb0minime: minimember; +2,418|7104

Basically the radar shoots out a signal and then some of that signal bounces back. If nothing bounces back, then it's completely clear, and depending on how much bounces back is based on clouds and rain. It's becoming a very common method of detecting storms and such nowadays. (Ever see any news stations bragging and advertising about "live doppler!" and shit like that? That's basically what this is).

This function describes the reflectivity of the rain, which is a function of droplet size (c) and number of droplets (N(D)).

2008-11-02 17:39:58

#11

Surgeons: U shud proabbly f off u fat prik; +3,097|6939|Gogledd Cymru

Why the fuck can't they do it the old fashioned way and check to see if the cows are lying down or not.

2008-11-02 17:45:21

#12

CammRobb: Banned; +1,510|6580|Carnoustie MASSIF

mtb0minime wrote:
Basically the radar shoots out a signal and then some of that signal bounces back. If nothing bounces back, then it's completely clear, and depending on how much bounces back is based on clouds and rain. It's becoming a very common method of detecting storms and such nowadays. (Ever see any news stations bragging and advertising about "live doppler!" and shit like that? That's basically what this is).

This function describes the reflectivity of the rain, which is a function of droplet size (c) and number of droplets (N(D)).

Wow, you're quite smart haha!

I've heard of doppler before actually.

2008-11-02 18:07:41

#13

God Save the Queen: Banned; +628|6793|tropical regions of london

dallas rains, johnny mountain

2008-11-02 18:08:34

#14

VicktorVauhn: Member; +319|6842|Southern California

Its probably integration by parts, but fuck that, that is a pita.

Buy Ti-89... actually if you want, PM me and I'll hook you up with a Ti-89 emulator...

Just did it on mine, and its a nasty long answer... if you just need to solve for N and C take the natural log and pull N and C out of the integral?

2008-11-02 18:10:29

#15

san4: The Mas; +311|7138|NYC, a place to live

I'm sure there's software that does integrals. And probably a web page somewhere that would do it for you.

2008-11-02 18:11:20

#16

mtb0minime: minimember; +2,418|7104

Actually it turns out integration by parts does work and I was just being an idiot. It takes a while to power through it and narrow down one of the factors to eventually disappear and make the integral manageable.

2008-11-02 19:28:53

#17

Flecco: iPod is broken.; +1,048|7115|NT, like Mick Dundee

Maths: A total fucking mystery.

Whoa... Can't believe these forums are still kicking.

2008-11-02 19:33:30

#18

Slarty: Member; +37|6414|Ingerland

The answer you're looking for is to open the window, stick your hand out and if it gets wet, it's raining.

Who needs radar

2008-11-02 19:43:32

#19

S.Lythberg: Mastermind; +429|6897|Chicago, IL

Chain rule in reverse? with substitution? that's just wicked man...

2008-11-02 19:52:28

#20

mtb0minime: minimember; +2,418|7104

S.Lythberg wrote:
Chain rule in reverse? with substitution? that's just wicked man...

Seriously! I can' handle doing a bajillion chain rules at once with a derivative, but integrals screw me over big time...

2008-11-02 19:56:21

#21

S.Lythberg: Mastermind; +429|6897|Chicago, IL

mtb0minime wrote:
S.Lythberg wrote:
Chain rule in reverse? with substitution? that's just wicked man...
Seriously! I can' handle doing a bajillion chain rules at once with a derivative, but integrals screw me over big time...

lol, that's why I have a whopping 41% in my calc III class (of course, that's actually passing by our standards, everyone fails)

2008-11-03 06:38:31

#22

mkxiii: online bf2s mek evasion; +509|6686|Uk

mtb0minime wrote:
mkxiii wrote:
what is the equivalent of x that will be taking the definite boundaries between 0 and infinite?
"D", hence the dD at the end

my god im a spastic

BF2S Forums Need Help With an Integral

1n_n07h1ng_w3_7ru57 wrote:

mkxiii wrote:

mtb0minime wrote:

S.Lythberg wrote:

mtb0minime wrote:

S.Lythberg wrote:

mtb0minime wrote:

mkxiii wrote:

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