Published by:
CGP EDU Academic Team
Published on: August 11, 2026
The equation 2sin 
. cos 2 x + sin 2 x = 2 sin 
. sin 2 x + cos 2 x has a root for which
A
sin2x = 1
B
sin2x = – 1
C
cosx = 
D
cos2x = – 
Text Solution
Verified by ExpertsThe correct answer is:
CHECK THE SOLUTION.
(a,b,c,d)
2sin 
. cos 2 x + sin 2 x = 2 sin 
. sin 2 x + cos 2 x ⇒ 2sin 
(cos 2 x – sin 2 x) = cos 2 x – sin 2 x
⇒ cos2x = 0 or 2sin 
= 1
⇒ sin2x = 1 or – 1 and cosx = 1 – 2sin 2 
= 
cos2x = 2cos 2 x – 1 = 2× 
– 1 = 
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