1
JEE Main 2019 (Online) 8th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
The sum $$\sum\limits_{k = 1}^{20} {k{1 \over {{2^k}}}} $$ is equal to
A
$$2 - {11 \over {{2^{19}}}}$$
B
$$2 - {3 \over {{2^{17}}}}$$
C
$$1 - {11 \over {{2^{20}}}}$$
D
$$2 - {21 \over {{2^{20}}}}$$
2
JEE Main 2019 (Online) 8th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If three distinct numbers a, b, c are in G.P. and the equations ax2 + 2bx + c = 0 and dx2 + 2ex + ƒ = 0 have a common root, then which one of the following statements is correct?
A
$$d \over a$$, $$e \over b$$, $$f \over c$$ are in G.P.
B
d, e, ƒ are in A.P
C
d, e, ƒ are in G.P
D
$$d \over a$$, $$e \over b$$, $$f \over c$$ are in A.P.
3
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The sum of all natural numbers 'n' such that 100 < n < 200 and H.C.F. (91, n) > 1 is :
A
3221
B
3121
C
3203
D
3303
4
JEE Main 2019 (Online) 12th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If sin4$$\alpha $$ + 4 cos4$$\beta $$ + 2 = 4$$\sqrt 2 $$ sin $$\alpha $$ cos $$\beta $$; $$\alpha $$, $$\beta $$ $$ \in $$ [0, $$\pi $$],
then cos($$\alpha $$ + $$\beta $$) $$-$$ cos($$\alpha $$ $$-$$ $$\beta $$) is equal to :
A
$$ - \sqrt 2 $$
B
0
C
$$-$$ 1
D
$$\sqrt 2 $$
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