Question:
If $a=3$ and $b=-2$, find the values of:
(i) $a^{a}+b^{b}$
(ii) $a^{b}+b^{a}$
(iii) $(a+b)^{a b}$
Solution:
(i) $a^{a}+b^{b}$
Here, $a=3$ and $b=-2$.
Put the values in the expression $a^{a}+b^{b}$.
$3^{3}+(-2)^{-2}$
$=27+\frac{1}{(-2)^{2}}$
$=27+\frac{1}{4}$
$=\frac{108+1}{4}$
$=\frac{109}{4}$
(ii) $a^{b}+b^{a}$
Here, $a=3$ and $b=-2$
Put the values in the expression $a^{b}+b^{a}$.
$3^{-2}+(-2)^{3}$
$=\left(\frac{1}{3}\right)^{2}+(-8)$
$=\frac{1}{9}-8$
$=\frac{1-72}{9}$
$=-\frac{71}{9}$
(iii) $(a+b)^{a b}$
Here, $a=3$ and $b=-2$
Put the values in the expression $(a+b)^{a b}$.
$[3+(-2)]^{3(-2)}$
$=(1)^{-6}$
$=1$