Question

How do i find the domain of f(x)=(x^4-16x^2)^1/2 [or the square root of x^4-16x^2] without a calculator?

Answer 1

\[\rm x^4 - 16x^2\ge0\]

Answer 2

Divide both sides by \(\rm x^2\).\[\rm x^2 - 16\ge0\]so\[(x + 4)(\rm x - 4)\ge 0\]

Answer 3

Actually...\[\rm x^2 > 16\]

Answer 4

For that,\[\rm |x|>4\]

Answer 5

**\[\rm |x|\ge 4\]