It is 9 because you need to triple 3 so 3x3 is 9
Explanation:
Note that
d
d
x
(
arccos
(
x
)
)
=
−
1
√
1
−
x
2
.
Then, by the chain rule
d
d
x
(
arccos
(
4
x
2
)
)
=
2
⋅
(
arccos
(
4
x
2
)
)
⋅
d
d
x
(
arccos
(
4
x
2
)
)
.
Then, by the chain rule again,
d
d
x
(
arccos
(
4
x
2
)
)
=
−
1
√
1
−
16
x
4
⋅
d
d
x
(
4
x
2
)
,
d
d
x
(
arccos
(
4
x
2
)
)
=
−
8
x
√
1
−
16
x
4
.
Substituting,
d
d
x
(
arccos
(
4
x
2
)
)
=
−
16
x
⋅
arccos
(
4
x
2
)
√
1
−
16
x
4
.
Answer:
5(4+√3)/13
Step-by-step explanation:
Answer:
21) 27
22) 2 (the third one has a few people in it)
Step-by-step explanation:
9 dozen= 12 to a dozen
108
=27