Solving two simultaneous power equations.

Posted 9 years ago
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 I'm trying to solve two equations to provide coefficients for a power function based on two data points. I'd consider this trivial with pen and paper, but I don't understand why Mathematica won't find an answer. I figure it's operator error - any idea what I'm missing? Thanks in advance!
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Posted 9 years ago
 Ah, thank you - I wasn't aware of that option for Solve. I am using 8.0.1.0.I noticed that MaxExtraConditions -> Automatic also gives a good solution. As a follow on question, is it possible for the Solve (or some another operator) to give 'a' as a function of 'b', even if not automatically? I often have to deal with problems such as this where one solution can be vastly simplified by substituting the expression of one of the other solutions. I tried hunting around but couldn't find an answer.
Posted 9 years ago
 I do not know how you obtained the above, since on V 10.02, it does not solve it as shown Clear[y1, x1, y2, x2, a, b]; eq1 = y1 == a*x1^b; eq2 = y2 == a*x2^b; Solve[{eq1, eq2}, {a, b}] gives  Solve::nsmet: "This system cannot be solved with the methods available to Solve. But you can get the solutions use this: Clear[y1, x1, y2, x2, a, b]; eq1 = y1 == a*x1^b; eq2 = y2 == a*x2^b; Solve[{eq1, eq2}, {a, b}, MaxExtraConditions -> All] 
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