Q. 7 B5.0( 1 Vote )

# If A = 30o, verify that :cos 2A = 1-2 sin2A=2cos2 A – 1

Answer :

Given: A =30o

Now, LHS = cos 2(30o)

cos 60o

Now, RHS = 1- 2sin2 A

1- 2sin2 (30o)

Now, RHS = 2cos2 A – 1

2cos2 (30o) - 1

LHS = RHS

Hence Proved

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