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#1
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how do I use the solver to solve polynomial equations?
I am using Excel 2000
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#2
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how do I use the solver to solve polynomial equations?
It is possible to use the quadratic formula for quadratic equations of the
form ax^2+bx+c. Solving for values of x use: (-b +or -(sqroot(b^2-4ac))/2a "Cameron PE" wrote: I am using Excel 2000 |
#3
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how do I use the solver to solve polynomial equations?
Nice in theory, bad idea in practice. Quoting (with slight editing for
this context) from Press, et al, /Numerical Recipes in C/: <quote If either a or c (or both) are small, then one of the roots will involve the subtraction of b from a very nearly equal quantity (the discriminant); you will get that root very inaccurately. The correct way to compute the roots is q = -(b + sgn(b)*sqrt(b^2-4a*c))*0.5 Then the two roots are x1 = q/a and x2 = c/q <end quote You can get this straight off of the web by searching for "Numerical Recipes in C", then look for Chapter 5. section 6 (Quadratic and Cubic Equations), pp 183 ff. Harlan Grove and I (and perhaps Jerry Lewis) had a thread on this some time back. I wrote the equations above to accommodate VBA to an extent. You may be able to rearrange things to make for a snappier function call, but you get the idea (I hope). Regards, Dave Braden CJ wrote: It is possible to use the quadratic formula for quadratic equations of the form ax^2+bx+c. Solving for values of x use: (-b +or -(sqroot(b^2-4ac))/2a "Cameron PE" wrote: I am using Excel 2000 -- Please keep response(s) solely within this thread. |
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