prove that : sin⁶0 + cos⁶0 =1 - 3 sin²0 cos² 0 ( 0 is thetha)
prove LHS = RHS
Answers
Answer:
Here I am using A instead of theta.
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We know the algebraic identities:
1 ) a³ + b³ = ( a + b )³ - 3ab( a + b )
2 ) a² + b² = ( a + b )² - 2ab
and
Trigonometric identity :
1 ) sin² A + cos² A = 1
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Now ,
i ) sin^6 A + cos^6A
= ( sin² A)³ + ( cos² A )³
=(sin²A+cos²A)³-3sin²Acos²A(sin²A+cos²A)
= 1 - 3sin²A cos²A --- ( 1 )
_____________________________
ii ) sin⁴A + cos⁴A
= ( sin² A )² + ( cos²A )²
= ( sin²A + cos²A )² - 2sin²Acos²A
= 1 - 2sin²Acos²A -----( ii )
__________________________
Now ,
LHS
= 2(sin^6A+cos^6A)-3(sin⁴A+cos⁴A)+1
{ From ( i ) & ( ii ) , we get }
=2(1 -3sin²Acos²A)-3(1 - 2sin²Acos²A)+1
= 2 -6sin²Acos²A-3+6sin²Acos²A + 1
= 2 - 3 + 1
= 3 - 3
= 0
= RHS
•••••
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Step-by-step explanation:
taking LHS,
0 +1
1
taking RHS
1-3×0×1
1
LHS = RHS