Question 898961

Find the domain of the function algebraically  f(x)= square root( x^4-16x^2)

Work: 
x^4-16x^2  > or equal to 0
x^2(x^2-16) > or equal to 0
x^2(x-4)(x+4) > or equal to 0
<pre>
That is the CORRECT work!!
At this stage: {{{x^2(x - 4)(x + 4) >= 0}}}, the CRITICAL POINTS are:
{{{system (- 4, 0_and, 4)}}}
Based on the critical points, the points and intervals that are solutions to the inequality are:
{{{highlight_green(highlight_green(system(x <= - 4, x = 0_and, x >= 4)))}}}