Solving x^4 - x^2 = k for x: Tips and Tricks to Simplify Equations

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SUMMARY

The equation x^4 - x^2 = k, where k > 0, can be solved by first factoring it into x^2(x^2 - 1) = k. By substituting y = x^2, the equation transforms into a quadratic function: y^2 - y - k = 0. This quadratic can be solved using the quadratic formula, and subsequently, the values of y can be used to find the corresponding values of x by taking the square root of y.

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Solve the equation [tex]x^4 - x^2 = k[/tex] where [itex]k>0[/itex].

Am I being thick or how do I solve this for [itex]x[/itex]?

Factorising gives [tex]x^2(x^2-1)=k[/tex] but now where?
 
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Let [itex]y= x^2[/itex] and that becomes a quadratic function:
[itex]y^2- y= k[/itex] or [itex]y^2- y- k= 0[/itex]. Solve that for y, then solve [itex]x^2= y[/itex] for x.
 

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