I'm really confused by this. I have the equation:

$\displaystyle f(x) = -2^x$

According toGraphthe function is supposed to look like the attached picture. But if you do an x-y table:

$\displaystyle

(X, Y)$

$\displaystyle (1, -2)$

$\displaystyle (2, 4)$

$\displaystyle (3, -8)$

$\displaystyle (-1, -\frac{1}{2})$

$\displaystyle (-2, \frac{1}{4})$

$\displaystyle (\frac{1}{2}, \sqrt {2}i)$

Could someone please explain to me how this works. Thanks.