My Mathematics is rusty.... can you solve this equation ?

[skippybangkok]

anyone with some more up to date maths skills ? 25 years back, no probs, not anymore. Trying to re look at the input of a non linear multiple regression

y=c+a1*z1+a2*z1^2+a3*z1^3+b1*z2+b2*z2^2+b3*z2^3

Looking to transpose the formula to z2=.......................

can't do it anymore

[Seastallion]

First step is to solve for (b₁ * z₂²⁾ + (b₃ * z₂³), to isolate z₂

y - (all the rest) = (b₁ * z₂²⁾ + (b₃ * z₂³)

Too many Hong Thiongs at this point.

[JesseFrank]

I tried to figure it out for you, but my calculator only has digits, no b's and z's on that bloody thing.

[Jdietz]

This help?

http://www.quickmath.com/webMathematica3/quickmath/equations/solve/basic.jsp#c=solve_stepssolveequation&v1=y%3Dc%2Ba1*z1%2Ba2*z1%5E2%2Ba3*z1%5E3%2Bb1*z2%2Bb2*z2%5E2%2Bb3*z2%5E3&v2=z2

[Seastallion]

This help?

http://www.quickmath.com/webMathematica3/quickmath/equations/solve/basic.jsp#c=solve_stepssolveequation&v1=y%3Dc%2Ba1*z1%2Ba2*z1%5E2%2Ba3*z1%5E3%2Bb1*z2%2Bb2*z2%5E2%2Bb3*z2%5E3&v2=z2

That makes more sense.

[Aussieroaming]

I got it z^2 = zzzzzzzzzzzzzzz

Let me get back to you tomorrow

[sdanielmcev]

tell me what * and ^ are supposed to mean, and I'll tell you. I'm very old school. Think clay tablets and Roman numerals.

[cobra]

[NeverSure]

Solve for X..jpeg

[NeverSure]

Oh what a headache. I can't do it. I can't get anything z^2.

I'm getting an end answer of 0 so I'm going back to bed.

Is this a trick question?

[skippybangkok]

Lol

Not a trick question. I am using multi variable non linear regression analysis to look at two inputs with relation to a known output.

I dug up a really cool spreadsheet which did the regression to the power of three.

result is a get a really cool regression line

Now I'm trying to use that to look back at original data to see whether it's underperforming or over performing

Using it for a real life application, Not a school project

Sent from my iPhone using Thaivisa Connect Thailand mobile app

[MJCM]

Ask Admin Tywais, he should be able to solve it.

Don't bother with us High school drop outs

Sent from my iPad so Please excuse any typos

[NeverSure]

The answer is zero.

[Mojomor]

OP, you Sir are off your whatever. You have 8 unknowns in 1 equation, A1, A2, A3, B1,B2, B3 plus Z1 and Z2. Please let me know, when you get out of the loony bin, and we can go for a few beers. Good Luck

[CharlieH]

Not Thai related

Closed