Sunday, 26 February 2017

Is it possible to to solve an equation with both power(?) and exponential terms for x?



If I have an equation of the form Y=A+xB+Cx is it possible to solve for x, where A, B, and C are all rational numbers?



More specifically, is it possible to solve y=12+2x+x1.92+20.425(x12) and, if so, how would I do it?


Answer



There is no nice formula that expresses x as a function of y. For any particular numerical value of y you can use software to find a value of x. For examples, if you ask Wolfram alpha to find x when y=100



solve  12+2x+x^1.92+2^(0.425(x−12))=100



you find out that y is



9.0984743836320913466


Since your function is increasing, it would be straightforward to write a python program (or a program in any other language) to find values by bisection, or to build a table of values as in a comment. You could even build a table of values in a spreadsheet.


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