1
JEE Main 2020 (Online) 4th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If $$A = \left[ {\matrix{ {\cos \theta } & {i\sin \theta } \cr {i\sin \theta } & {\cos \theta } \cr } } \right]$$, $$\left( {\theta = {\pi \over {24}}} \right)$$

and $${A^5} = \left[ {\matrix{ a & b \cr c & d \cr } } \right]$$, where $$i = \sqrt { - 1} $$ then which one of the following is not true?
A
$$a$$2 - $$c$$2 = 1
B
$$0 \le {a^2} + {b^2} \le 1$$
C
$$ a$$2 - $$d$$2 = 0
D
$${a^2} - {b^2} = {1 \over 2}$$
2
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
Let A be a 3 $$ \times $$ 3 matrix such that
adj A = $$\left[ {\matrix{ 2 & { - 1} & 1 \cr { - 1} & 0 & 2 \cr 1 & { - 2} & { - 1} \cr } } \right]$$ and B = adj(adj A).

If |A| = $$\lambda $$ and |(B-1)T| = $$\mu $$ , then the ordered pair,
(|$$\lambda $$|, $$\mu $$) is equal to :
A
(3, 81)
B
$$\left( {9,{1 \over 9}} \right)$$
C
$$\left( {3,{1 \over {81}}} \right)$$
D
$$\left( {9,{1 \over {81}}} \right)$$
3
JEE Main 2020 (Online) 3rd September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If $$\Delta $$ = $$\left| {\matrix{ {x - 2} & {2x - 3} & {3x - 4} \cr {2x - 3} & {3x - 4} & {4x - 5} \cr {3x - 5} & {5x - 8} & {10x - 17} \cr } } \right|$$ =

Ax3 + Bx2 + Cx + D, then B + C is equal to :
A
-1
B
-3
C
9
D
1
4
JEE Main 2020 (Online) 2nd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Let A = {X = (x, y, z)T: PX = 0 and

x2 + y2 + z2 = 1} where

$$P = \left[ {\matrix{ 1 & 2 & 1 \cr { - 2} & 3 & { - 4} \cr 1 & 9 & { - 1} \cr } } \right]$$,

then the set A :
A
is an empty set.
B
contains more than two elements.
C
contains exactly two elements.
D
is a singleton.
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