1
WB JEE 2019
MCQ (Single Correct Answer)
+1
-0.25
Change Language
Let the relation $$\rho $$ be defined on R as a$$\rho $$b if 1 + ab > 0. Then,
A
$$\rho $$ is reflexive only.
B
$$\rho $$ is equivalence relation.
C
$$\rho $$ is reflective and transitive but not symmetric.
D
$$\rho $$ is reflexive and symmetric but not transitive.
2
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
Let f : X $$ \to $$ Y and A, B are non-void subsets of Y, then (where the symbols have their usual interpretation)
A
$${f^{ - 1}}(A) - {f^{ - 1}}(B) \supset {f^{ - 1}}(A - B)$$ but the opposite does not hold.
B
$${f^{ - 1}}(A) - {f^{ - 1}}(B) \subset {f^{ - 1}}(A - B)$$ but the opposite does not hold.
C
$${f^{ - 1}}(A - B) = {f^{ - 1}}(A) - {f^{ - 1}}(B)$$
D
$${f^{ - 1}}(A - B) = {f^{ - 1}}(A) \cup {f^{ - 1}}(B)$$
3
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
Let S, T, U be three non-void sets and f : S $$ \to $$ T, g : T $$ \to $$ U be so that gof : s $$ \to $$ U is surjective. Then,
A
g and f are both surjective
B
g is surjective, f may not be so
C
f is surjective, g may not be so
D
f and g both may not be surjective
4
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
On R, a relation $$\rho $$ is defined by x$$\rho $$y if and only if x $$-$$ y is zero or irrational. Then,
A
$$\rho $$ is equivalence relation
B
$$\rho $$ is reflexive but neither symmetric nor transitive
C
$$\rho $$ is reflexive and symmetric but not transitive
D
$$\rho $$ is symmetric and transitive but not reflexive
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CBSE
Class 12