Q14. 2(sin6 θ + cos6 θ) – 3(sin4 θ + cos4 θ) is equal to
Question
(a) 0
(b) 6
(c) -1
(d) None of these
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Class 10 Maths
3 years
2021-12-23T11:00:42+00:00
2021-12-23T11:00:42+00:00 1 Answer
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Answer ( 1 )
Answer: (c) -1
2(sin6θ+cos6θ)−3(sin4θ+cos4θ)+1
=2{(sin2θ+cos2θ)3−3sin2θcos2θ(sin2
θ+cos2θ)}−3(sin2θ+cos2θ)2−2(sin2θc
os2θ)}+1
We know, [sin2x+cos2x=1]
=2{1−3sin2θcos2θ}−3{1−2sin2θcos2θ
}+1