Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

You are not logged in.

## #1 2005-03-07 20:55:12

Su165
Member
Registered: 2005-03-07
Posts: 1

### Help ASAP

Can anyone give me a hand with this, cause I'm stumped and can't remember exactly how to go about solving this.

here's the eqn

m[d^2x/dt^2 + wsubo^2 x] = F cos wt

I'm supposed to show that x(t) = xsubo cos wt

w is the incident freq
wsubo is the resonant freq
m is mass

I'm guessing it has to be shown by undetermined coefficients but I can't find the right path exactly.

Offline

## #2 2005-03-07 21:35:36

MathsIsFun
Registered: 2005-01-21
Posts: 7,686

### Re: Help ASAP

A bit outside my area, but I found a website that has ALL sorts of stuff about harmonic motion which could help here

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Offline

## #3 2005-03-17 08:04:56

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

### Re: Help ASAP

Um...what kind of algebra is that?

School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

Offline

## #4 2005-03-17 08:17:36

MathsIsFun
Registered: 2005-01-21
Posts: 7,686

### Re: Help ASAP

The difficult kind ! It has calculus in it.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Offline

## #5 2005-03-17 08:51:11

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

### Re: Help ASAP

How old are you expected to be to be at that standard?

School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

Offline

## #6 2005-03-17 09:19:23

MathsIsFun
Registered: 2005-01-21
Posts: 7,686

### Re: Help ASAP

Depends on where you live. Some countries start Calculus in the final year of high school.

But usually Universities teach it in the first year.

I was thinking of putting a small introduction to it on this website.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Offline

## #7 2005-03-17 09:24:07

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

### Re: Help ASAP

I'm only thirteen!

School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

Offline

## #8 2005-03-17 09:47:45

MathsIsFun
Registered: 2005-01-21
Posts: 7,686

### Re: Help ASAP

You're doing well!

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Offline

## #9 2005-03-18 05:30:54

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

### Re: Help ASAP

Thank you.....but how do you know....?

School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

Offline

## #10 2005-03-18 08:52:27

MathsIsFun
Registered: 2005-01-21
Posts: 7,686

### Re: Help ASAP

You noticed, and were curious about, the algebra. You write well, too.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Offline

## #11 2005-03-19 07:35:19

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

### Re: Help ASAP

You're such a nice person!

School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

Offline