Question

for what of x will square root of x^2-4 represent a real number??

Answer 1

x >= 2, to make sure that you don't have a negative result within the radical sign...

Answer 2

if the result within or inside the radical becomes negative then you'll have an imaginary number not a real number...

Answer 3

how??

Answer 4

i dunno how to get it O.O

Answer 5

solving for x, by equating the whole expression to zero and square it....

Answer 6

\[\sqrt{(x^2-4)}\ge0\]\[x^2-4\ge0\]\[x^2\ge4\]
so either \[x \ge2 \quad or \quad x \le -2\]
because a square is always positive

Answer 7

there you are...

Answer 8

It will always be a positive real result unless the (x^2-4) is less than 0. Which will only happen if -2<x<2

Answer 9

that's more clear than mine... :)

Answer 10

how help please :(

Answer 11

What don't you understand?