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Question
3[sin4(3π2α)+sin4(3π+α)][sin6(π2+α)+sin6(5πα)]
Options:
A .  0
B .  1
C .  3
D .  sin 4α + sin 6α
Answer: Option B
:
B
(b) 3[sin4(3π2α)+sin4(3π+α)] - [sin6(π2+α)+sin6(5πα)]
=3(cosα)4+(sinα)42cos6α+sin6α
=3(cos2α+sin2α)22sin2αcos2α2(cos2α+sin2α)33sin2αcos2α(cos2α+sin2α)
=36sin2αcos2α2+6sin2αcos2α=32=1
Trick: Put α=0 , the value of expressions remains 1 i.e., it is independent of α

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