Limit as x approaches 0 of (square root(4+x^4)-2)/x^4)

[famallama]

limit as x approaches 0 of (square root(4+x^4)-2)/x^4)
it says to solve algebraically by rationalizing the numerator

 

[Dick]

To rationalize it multiply numerator and denominator by sqrt(4+x^4)+2. Use (a+b)*(a-b)=a^2-b^2.