2
$\begingroup$

When solving

$\ln(x^2+1) = \ln(x) + 2$

I'm getting stuck at

$e^2 = \dfrac{x^2+1}{x}$

How do I isolate $x$?

  • 1
    Write as a quadratic equation and solve for $x$.2012-05-27

1 Answers 1

7

$$e^2=\frac{x^2+1}{x}\Longleftrightarrow x^2-e^2x+1=0$$

and you have a simple quadratic to solve.

  • 2
    I think the OP doesn't know how to. Assuming he doesn't, I'd add the quadratic solution : $ax^2+bx+c$, the solutions are $ x = \frac{-b\pm \sqrt{b^2-4ac}}{2a}$.2012-05-27
  • 0
    Don't worry, I do know about how to solve quadratic equations. ;-)2012-05-27