# Math Help - My big problem

1. ## My big problem

Hello
I have a problem with a function,
Is it posible to calculate it, if hte exp is 10 or
maybe a number between 6 and 10 (6,7,8,9,10)

y = P - A x + B x^2 C y^a

How can I find y?

P,A,B,C,a are constants

Thank you very much

2. Originally Posted by Rinol
Hello
I have a problem with a function,

y = P - A x + B x^2 C y^a

How can I find y?

P,A,B,C,a are constants

Thank you very much
If a= 2 that is a quadratic equation in y and you can use the quadratic formula. If a= 3 or 4, it is a cubic or quartic equation, respectively, and there are formulas for solving for y (but much more complicated than the quadratic equation!). If a= 1/2, you can let z= y^(1/2) then you get z^2= P- Ax+ Bx^2 z, a quadratic equation in z. You can use the quadratic formula to solve for z and then take the square root find y. If a= 1/3 or 1/4, similarly, let z= y^(1/3) or z= y^(1/4) respectively to get polynomial equations that can be solved for z.

If a not one of those numbers, there are no general formulas for solving such an equation.

3. Originally Posted by Rinol
y = P - A x + B x^2 C y^a
Are you sure you posted that properly?

Could the "y" on the left be a typo?

4. ## My big problem

Hallo everybody,

I posted my problem last week
but now I know my exponent, it is 10.

I need to get the therm for y!

y = P - Ax + BC x^2 y^10

P,A,B,C are constants!

Thanks a lot

5. Originally Posted by Rinol
I need to get the therm for y!
y = P - Ax + BC x^2 y^10
Let u = BC x^2 and v = P - Ax; then:
y = v + u y^10
u y^10 - y = -v
y(u y^9 - 1) = -v

I see iteration as the only way to solve this