prove that sin^4A- cos^4A = 1-2cosA
ayusmanpatra04p9a3it:
Hey omm414... I think the que. will be sin^4A- cos^4A = 1-2cos²A
the rhs is wrong
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Hey dear friend
Sin⁴A-Cos⁴A=1-2CosA
Taking L.H.S.
we can write
(Sin²A)²-(Cos²A)²
[By id. (a+b)(a-b)=a²-b²]
(Sin²A+Cos²A)(Sin²A-Cos²A)
[By id. (Sin²A+Cos²A)=1 ]
1(Sin²A-Cos²A)
[By I'd. Sin²A+Cos²A=1 ]
(1-Cos²A-Cos²A)
(1-2cos²A) = (1-2cos²A)
As L.H.S.= R.H.S.
Hence Proved
perfectly fine pure correct answer
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Sin⁴A-Cos⁴A=1-2CosA
Taking L.H.S.
we can write
(Sin²A)²-(Cos²A)²
[By id. (a+b)(a-b)=a²-b²]
(Sin²A+Cos²A)(Sin²A-Cos²A)
[By id. (Sin²A+Cos²A)=1 ]
1(Sin²A-Cos²A)
[By I'd. Sin²A+Cos²A=1 ]
(1-Cos²A-Cos²A)
(1-2cos²A) = (1-2cos²A)
As L.H.S.= R.H.S.
Hence Proved
perfectly fine pure correct answer
hope it helps you mark me as brainliest and follow me
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