MC
1
2
3
4
5
6
7
8
Maximum
2
2
2
2
2
2
2
2
Note
9
10
11
12
13
14
15
16
Total
bonus!
3
3
4
7
7
3
7
3
50+3
Multiple choice
Questions 1 to 8 are
multiple choice
and each is worth 2 points. No need for justification in Multiple
choice.
Question 1.
The domain of
f
(
x
) =
r
x
x
2
−
4
is:
A.
(
−∞
,
−
2)
∪
(0
,
1]
B.
(
−∞
,
−
2]
∪
[0
,
1]
C.
(
−
2
,
0]
∪
(2
,
∞
)
D.
(
−∞
,
−
2)
E.
[
−
2
,
0)
∪
[2
,
∞
)
F.
(2
,
∞
).
Answer:
Answer:
C
Note that the denominator MUST not be zero:
x
2
−
4
̸
= 0 or (
x
−
2)(
x
+ 2)
̸
= 0, so
x
̸
= 2 and
x
̸
=
−
2. NEXT:
Case 1.
x
≥
0 and
x
2
−
4 = (
x
−
2)(
x
+ 2)
>
0, hence
x
∈
[0
,
∞
) and
x
∈
(
−∞
,
−
2)
∪
(2
,
∞
). INTERSECT (see
word AND) and we get:
x
∈
(2
,
∞
).
Case 2.
x
≤
0 and
x
2
−
4 = (
x
−
2)(
x
+ 2)
<
0, hence
x
∈
[
−∞
,
0] and
x
∈
(
−
2
,
2). INTERSECT and we get:
x
∈
(
−
2
,
0].
Union of the two cases gives C. Happy? HS stuff as u can see.