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Re: Help me please!!!

• To: mathgroup at smc.vnet.net
• Subject: [mg5815] Re: [mg5770] Help me please!!!
• From: BobHanlon at aol.com
• Date: Wed, 22 Jan 1997 00:44:17 -0500
• Sender: owner-wri-mathgroup at wolfram.com

>> I must invert this function: y = (x^2) + x     for x >= 0

In Mathematica:

Select[Solve[ y == x^2 + x, x ], (x /. (# /. y -> 1)) > 0&]

or by hand just use quadratic equation for solving

x^2 + x - y == 0

and select solution which provides nonnegative values for x (+Sqrt[]).


Bob Hanlon