aM^12 + bM^2 + c = 0

Hi,

I am currently conducting research on High Speed Aerodynamics and I am having some real trouble with a particular equation.

(A/A*)^2 = (1/M^2)*[(2/(g+1))*(1 + ((g-1)M^2)/2)]^((g + 1)/(g - 1))

n.b This equation is called the area Mach number relation equation.

where A, A* and g are known (967.59, 881.41 and 1.4 respectively) and M is to be found.

From tables and previous research I know there should be two values for M, roughly 1.35 and 0.75.

If anyone can help I would be extremely grateful and you would get a mention in my final published research paper.

Thank you very much for taking the time to read this.

David James

Just use Maple or Mathematica or something to evaluate it.

I tried plotting it on my calc and from x=0 to x=5, y (M) was always 1.2832, always. maybe my fault, but I did double check it.