2006 Cyprus MO/Lyceum/Problem 3

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Problem

The domain of the function $f(x)=\sqrt{4+2x}$ is

$\mathrm{(A)}\ (-2,+\infty)\qquad\mathrm{(B)}\ [0,+\infty)\qquad\mathrm{(C)}\ [-2,+\infty)\qquad\mathrm{(D)}\ [-2,0]\qquad\mathrm{(E)}\ \mathbb{R}$

Solution

$2x+4$ must be non-negative, so $x+2$ must be non-negative.

Therefore, all $x\ge-2$ are in the domain $\mathrm{(C)}$.

See also

2006 Cyprus MO, Lyceum (Problems)
Preceded by
Problem 2
Followed by
Problem 4
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