Browse Questions

# The Domain of $f(x)=\large^{7-x}P_{x-3}$ is ?

(A) $(-\infty,7]$

(B) $[3,\infty)$

(C) $\{3,4,5\}$

(D)$[3,7]$
Can you answer this question?

For $\large^{7-x}P_{x-3}$ to exist
$7-x\geq 0,\:\:\:\:x-3\geq 0\:\:and\:\:7-x\geq x-3$
$\Rightarrow\:x\leq 7,\:\:\:x\geq 3\:\:and\:\:x\leq 5$
$\Rightarrow\:$ $x \in \{3,4,5\}$
answered May 25, 2013