1
JEE Main 2022 (Online) 27th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The value of $$\cos \left( {{{2\pi } \over 7}} \right) + \cos \left( {{{4\pi } \over 7}} \right) + \cos \left( {{{6\pi } \over 7}} \right)$$ is equal to :

A
$$-$$1
B
$$-$$$${1 \over 2}$$
C
$$-$$$${1 \over 3}$$
D
$$-$$$${1 \over 4}$$
2
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

$$16\sin (20^\circ )\sin (40^\circ )\sin (80^\circ )$$ is equal to :

A
$$\sqrt 3 $$
B
2$$\sqrt 3 $$
C
3
D
4$$\sqrt 3 $$
3
JEE Main 2022 (Online) 25th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The value of 2sin (12$$^\circ$$) $$-$$ sin (72$$^\circ$$) is :

A
$${{\sqrt 5 (1 - \sqrt 3 )} \over 4}$$
B
$${{1 - \sqrt 5 } \over 8}$$
C
$${{\sqrt 3 (1 - \sqrt 5 )} \over 2}$$
D
$${{\sqrt 3 (1 - \sqrt 5 )} \over 4}$$
4
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The value of

$$2\sin \left( {{\pi \over 8}} \right)\sin \left( {{{2\pi } \over 8}} \right)\sin \left( {{{3\pi } \over 8}} \right)\sin \left( {{{5\pi } \over 8}} \right)\sin \left( {{{6\pi } \over 8}} \right)\sin \left( {{{7\pi } \over 8}} \right)$$ is :
A
$${1 \over {4\sqrt 2 }}$$
B
$${1 \over 4}$$
C
$${1 \over 8}$$
D
$${1 \over {8\sqrt 2 }}$$
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