MCQ
If $a = -2, b = -1,$ than $a^b-b^a$ is equal to:
- A$0.5$
- B$-1$
- C$-2$
- ✓$-1.5$
✓
Answer
Correct option: D.
$-1.5$
$a^b-b^a$
$= (-2)^{-1}(-1)^{-2}$
$=\frac{1}{(-2)}-\frac{1}{(-1)^2}$
$=\frac{-1}{2}-1$
$=\frac{-3}{2}$
$=-1.5$
$= (-2)^{-1}(-1)^{-2}$
$=\frac{1}{(-2)}-\frac{1}{(-1)^2}$
$=\frac{-1}{2}-1$
$=\frac{-3}{2}$
$=-1.5$
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