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1 vote
1-cos2a/2cosa=sina.tana​

User Safiyyah
by
8.3k points

1 Answer

2 votes

Answer:

see explanation

Explanation:

using the trigonometric identities

• cos2a = 1 - 2sin²a

• tana =
(sina)/(cosa)

consider the left side


(1-cos2a)/(2cosa)

=
(1-(1-2sin^2a))/(2cosa)

=
(1-1+2sin^2a)/(2cosa)

=
(2sin^2a)/(2cos^2a) ← cancel the 2 on the numerator/ denominator

=
(sin^2a)/(cosa)

= sina ×
(sina)/(cosa)

= sina × tana

= sinatana

= right side

User Jedd
by
7.8k points

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