OT: Looking for a good physics site

[Fyron]

Why are you randomly rewriting the equation? The way to solve a quadratic equation has already been posted..

Why are you starting with a complete set of values, including time and distance, that you plug in to verify the refactored equations? Where are they coming from?

[narf poit chez BOOM]

If you thought that was random, you need to look again. I was de-rusting my algebra skills. I know I wasn't using the method that was posted; that was not the point. I was working off the theory that if 'T' is used to solve the equation, then some permutation of the equation could be used to solve for T.

I did not start with a distance value. I calculated it. I use a complete set of values for the simple reason that I can use them to see if the refactored equation is the correct one.

[Fyron]

Getting T^3 as the only factor with T out of a quadratic polynomial looks entirely random to me.

[Jack Simth]

Google is your friend.

Looks like someone already did the work.

[narf poit chez BOOM]

@Fyron: Hence why I need to de-rust my algebra skills. It's the circle of maaaaath...

@Jack: I did try google. More than once.

[narf poit chez BOOM]

Well, I read it and I get the general idea...

Would these be the equations to use? (After removing the 'Z' terms)
Code:

---

0 = ( (1/4) * (Tax2 + Tay2 + Taz2 - Pam2) ) * t4 +

    ( Tax * Tvx + Tay * Tvy + Taz * Tvz - Pam * Pvm ) * t3 +

    ( Tax * Tpx + Tvx2 + Tay * Tpy + Tvy2 + 

        Taz * Tpz + Tvz2 - Pam * Ppm - Pvm2 ) * t2 +

    ( 2 * ( Tvx * Tpx + Tvy * Tpy + Tvz * Tpz - Pvm * Ppm ) ) * t +

    ( Tpx2 + Tpy2 + Tpz2 - Ppm2 )

---

Code:

---

P't2 = ( Pam2 * Rbt2 + 2 * Pam * Pvm * Rbt + Pvm2 ) * t2 +

  ( 2 * Pam * Ppm * (Pam * Rbt + Pvm) - Pam2 * Rbt3 - Pam * Pvm * Rbt2 ) * t +

  ( (1/4) * Pam2 * Rbt4 - Pam * Ppm * Rbt2 + Ppm2 )

---

[narf poit chez BOOM]

Yaay, the .dll works! Thank you Jack, thank you Fyron, thank you SJ, thank you everyone else who helped!

(Now, I just have to figure out how to modify the .dll for a matching intercept...)

[Renegade 13]

I remember now why I hate math!

[AngleWyrm]

narf poit chez BOOM said:I was working off the theory that if 'T' is used to solve the equation, then some permutation of the equation could be used to solve for T.

Given: D = (1/2) * A * T^2 + V * T + P

T = (-V +/- Sqrt(2AD-2AP+V^2) )/A

A = 5
T = 3
P = 50
V = 15
D = 117.5

3=(-15 +/- Sqrt(2x5x117.5 - 2x5x50 + 15^2))/5
3=(-15 +/- Sqrt(1175 - 500 + 225))/5
3=(-15 +/- Sqrt(900))/5
3=( -15 +/- 30 )/5
3=( 15 or -45 )/5
3=( 3 or -9)

Also:
V = ((D-P)/T) - AT/2
P = D - (T(AT+2V))/2
A = -( (2(-D+P+TV))/T^2 )

--
Mathematica: The new calculator

[narf poit chez BOOM]

Thanks!