hi

how can i proof :( :

$\displaystyle

v=(mu/a)^{1/2} (1+e cosE/1-e cosE)^{1/2}

$

where $\displaystyle v =(v_{Ap}^2 + v_{peri}^2)^{1/2}$

if the planet orbit on ellipse ???

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- May 23rd 2006, 12:43 AMsweetneed help!!
hi

how can i proof :( :

$\displaystyle

v=(mu/a)^{1/2} (1+e cosE/1-e cosE)^{1/2}

$

where $\displaystyle v =(v_{Ap}^2 + v_{peri}^2)^{1/2}$

if the planet orbit on ellipse ??? - May 23rd 2006, 02:57 AMCaptainBlackQuote:

Originally Posted by**sweet**

we are guessing what you have been asked to prove, I assume it is:

$\displaystyle

v=(mu/a)^{1/2} \left(\frac{1+e\ \cos(E)}{1-e\ \cos(E)}\right)^{1/2}

$

but that leaves us guessing is $\displaystyle mu$ supposed to be $\displaystyle \mu$?

Is $\displaystyle e$ the eccentricity? $\displaystyle a$ the semi-major axis?

Also what is $\displaystyle E$?

We can guess but it is just making it more work for the helpers here.

RonL - May 23rd 2006, 04:23 AMsweet
ok ;)

mu = $\displaystyle

\mu

$

e= the eccentricity

a= the semi-major axis

E=the eccentric anomaly

we want to proof

$\displaystyle

v=(\mu/a)^{1/2} \left(\frac{1+e\ \cos(E)}{1-e\ \cos(E)}\right)^{1/2}

$

if the planet orbit on ellipse ???

where

$\displaystyle

v =(v_{Ap}^2 + v_{peri}^2)^{1/2}

$

Thanks for helping me! - May 23rd 2006, 06:21 AMCaptainBlackQuote:

Originally Posted by**sweet**

planet in its orbit and v as defined here is a constant, as are e mu and a

this cannot be true for almost all values of eccentricity.

Or have I misunderstood something?

RonL - May 23rd 2006, 07:53 AMsweet
E divined like in the graph

and v isn't constant it's a Velocity - May 23rd 2006, 08:41 AMCaptainBlackQuote:

Originally Posted by**sweet**

$\displaystyle

v =(v_{Ap}^2 + v_{peri}^2)^{1/2}

$ - May 23rd 2006, 09:08 AMsweet
$\displaystyle v_{AP}$ is Aphelion Velocity

$\displaystyle v_{peri}$ is pericentre Velocity

and v is aggregate of $\displaystyle v_{AP} ,v_{peri}$

so

$\displaystyle

v^2=v_{peri}^2+v_{AP}^2

$ - May 23rd 2006, 09:11 AMCaptainBlackQuote:

Originally Posted by**sweet**

RonL - May 23rd 2006, 09:15 AMsweetQuote:

Originally Posted by**CaptainBlack**

why u say it's constant

:confused: :confused: - May 23rd 2006, 12:44 PMtopsquarkQuote:

Originally Posted by**sweet**

-Dan - May 23rd 2006, 12:52 PMsweetQuote:

Originally Posted by**topsquark**

i'm sorry it's Perihelion velocity not pericenter velocity :rolleyes: - May 24th 2006, 12:45 PMtopsquarkQuote:

Originally Posted by**sweet**

-Dan - May 24th 2006, 03:21 PMsweetQuote:

Originally Posted by**topsquark**

$\displaystyle

v=(mu/a)^{1/2} \left(\frac{1+e\ \cos(E)}{1-e\ \cos(E)}\right)^{1/2}

$

it,s verey hard .... - May 25th 2006, 03:37 AMtopsquarkQuote:

Originally Posted by**sweet**

-Dan - May 25th 2006, 09:29 AMCaptainBlackQuote:

Originally Posted by**topsquark**

RonL