1
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
Let f : A $$\to$$ B be a function defined as f(x) = $${{x - 1} \over {x - 2}},$$ Where A = R $$-$$ {2} and B = R $$-$$ {1}. Then   f   is :
A
invertible and $${f^{ - 1}}(y) =$$ $${{3y - 1} \over {y - 1}}$$
B
invertible and $${f^{ - 1}}\left( y \right) = {{2y - 1} \over {y - 1}}$$
C
invertible and $${f^{ - 1}}\left( y \right) = {{2y + 1} \over {y - 1}}$$
D
not invertible
2
JEE Main 2017 (Online) 9th April Morning Slot
+4
-1
The function f : N $$\to$$ N defined by f (x) = x $$-$$ 5 $$\left[ {{x \over 5}} \right],$$ Where N is the set of natural numbers and [x] denotes the greatest integer less than or equal to x, is :
A
one-one and onto
B
one-one but not onto.
C
onto but not one-one.
D
neither one-one nor onto.
3
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1
Let f(x) = 210.x + 1 and g(x)=310.x $$-$$ 1. If (fog) (x) = x, then x is equal to :
A
$${{{3^{10}} - 1} \over {{3^{10}} - {2^{ - 10}}}}$$
B
$${{{2^{10}} - 1} \over {{2^{10}} - {3^{ - 10}}}}$$
C
$${{1 - {3^{ - 10}}} \over {{2^{10}} - {3^{ - 10}}}}$$
D
$${{1 - {2^{ - 10}}} \over {{3^{10}} - {2^{ - 10}}}}$$
4
JEE Main 2017 (Offline)
+4
-1
The function $$f:R \to \left[ { - {1 \over 2},{1 \over 2}} \right]$$ defined as

$$f\left( x \right) = {x \over {1 + {x^2}}}$$, is
A
invertible
B
injective but not surjective.
C
surjective but not injective
D
neither injective nor surjective.
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