Independent Variable in Solver affect the result

Hi ruecel,

Solver was updated in Excel 2010. See https://blogs.office.com/2009/09/21/...proved-solver/

From my college days, many decades ago, YES it is important to give an initial starting value that converges to an answer. In that class we found some functions don't converge and other methods need to be used to find an answer. It was with great interest that sometimes there is no real answer to questions and therefore solver doesn't work. An example of this would be find where the roots of X^2 +5 . This means where x^2 + 5 cross the x axis on a graph. It simply doesn't cross the X axis so Solver fails.

The example above is pretty simple but sometimes we are asked to solve impossible functions. I do believe the initial guess needs some study before solver gives the answer you are looking for.

Solver's default algorithm is an expanded version of Newton's method for finding roots. I like to point people to this page: http://www.cs.utah.edu/~zachary/isp/...ot/Newton.html The applet will show you how Newton's method works, as well as occasions when it will fail. Understanding how Newton's method works will help you understand how Solver works and why your choice of initial guess can be crucial to finding a solution.