Question

prove that question answer it pls​

Answer 1

Step-by-step explanation:

Proof :-

We have , LHS

( 1 - cos 3A ) / ( 1 - cos A )

= (1 - 4 cos^3 A + 3 cos A + cos A - cosA ) ( 1- cosA )

= ( 1- cos A + 4 cos A - 4 cos ^3A) / ( 1- cos A )

= ( 1- cos A) / ( 1- cosA ) + 4 cosA ( 1- cos^2A)/(1- cosA)

= 1 + 4 cosA ( 1 + cos A)

= 1 + 4 cos A + 4 cos^2A

= ( 1 + 2 cos A) ^2

Hence , proved

Answer 2

Step-by-step explanation:

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