(a) Let = { ∈ : − 1 < < 1} and : → be defined by () =
1+||
, ∈ .
Show that is a bijection.
Answers
Answer:
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Step-by-step explanation:
A=R−{3} and B=R−{1}
one−one:
We have, f(x)=
x−3
x−2
Calculate f(x
1
):
⇒ f(x
1
)=
x
1
−3
x
1
−2
Calculate f(x
2
):
⇒ f(x
2
)=
x
2
−3
x
2
−2
Now, f(x
1
)=f(x
2
)
⇒
x
1
−3
x
1
−2
=
x
2
−3
x
2
−2
⇒ (x
1
−2)(x
2
−3)=(x
2
−2)(x
1
−3)
⇒ x
1
x
2
−3x
1
−2x
2
+6=x
1
x
2
−3x
2
−2x
1
+6
⇒ −x
1
=−x
2
⇒ x
1
=x
2
∴ f is an one-one function.
onto:
Let y∈B=R−{1}
Then, y
=1.
The function f is onto if there x∈A such that f(x)=y.
Now,
⇒ f(x)=y
⇒
x−3
x−2
=y
⇒ x−2=xy−3y
⇒ x(1−y)=−3y+2
⇒ x=
1−y
2−3y
∈A [ y
=1]
Thus, for any y∈B, there exists
1−y
2−3y
∈A such that
⇒ f(
1−y
2−3y
)=
(
1−y
2−3y
)−3
(
1−y
2−3y
)−2
=
2−3y−3+3y
2−3y−2+2y
=
−y
−y
=y
∴ f(
1−y
2−3y
)=y
∴ f is onto.