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Question
Mathematics
The inverse function of f(x) = (82x-8-2x/82x + 8-2x), xϵ (-1, 1), is .
Q. The inverse function of
f
(
x
)
=
8
2
x
+
8
−
2
x
8
2
x
−
8
−
2
x
,
x
ϵ
(
−
1
,
1
)
,
is __________.
4122
194
JEE Main
JEE Main 2020
Relations and Functions - Part 2
Report Error
A
4
1
(
l
o
g
8
e
)
l
o
g
e
(
1
+
x
1
−
x
)
20%
B
4
1
(
l
o
g
8
e
)
l
o
g
e
(
1
−
x
1
+
x
)
38%
C
4
1
l
o
g
e
(
1
−
x
1
+
x
)
25%
D
4
1
l
o
g
e
(
1
+
x
1
−
x
)
17%
Solution:
f
(
x
)
=
y
=
8
4
x
+
1
8
4
x
−
1
=
1
−
8
4
x
+
1
2
so,
8
4
x
+
1
=
1
−
y
2
⇒
8
4
x
=
1
−
y
1
+
y
⇒
x
=
ℓ
n
(
1
−
y
1
+
y
)
×
4
ℓ
n
8
1
=
f
−
1
(
y
)
Hence,
f
−
1
(
x
)
=
4
1
l
o
g
g
e
ℓ
n
(
1
−
x
1
+
x
)