f(x) = x / sqrt(x+4)
x + 4 = 0
x = -4
OK, so the domain can't include -4 BUT why is it all real numbers greater than -4?
Answer: Domain is all real numbers greater than -4
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Because in must be greater than or equal to 0 (at least if you want it to be real..)
Originally Posted by james_bond Because in must be greater or equal to 0. Can't you have a negative inside a square root?
Only if you're familiar with complex numbers, see here.
Hmmm, another question...how come this is different then?
f(x) = x / sqrt( abs(x) - 4 )
Answer: (-infinity, -4) U (4, infinity)
Can you solve it now?
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