1
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
For any non-zero complex number z, the minimum value of | z | + | z $$-$$ 1 | is
A
1
B
$${{1 \over 2}}$$
C
0
D
$${{3 \over 2}}$$
2
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
The system of equations

$$\eqalign{ & \lambda x + y + 3z = 0 \cr & 2x + \mu y - z = 0 \cr & 5x + 7y + z = 0 \cr} $$

has infinitely many solutions in R. Then,
A
$$\lambda $$ = 2, $$\mu $$ = 3
B
$$\lambda $$ = 1, $$\mu $$ = 2
C
$$\lambda $$ = 1, $$\mu $$ = 3
D
$$\lambda $$ = 3, $$\mu $$ = 1
3
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
$${f^{ - 1}}(A - B) = {f^{ - 1}}(A) \cup {f^{ - 1}}(B)$$
4
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
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