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Question Number 115685 by ZiYangLee last updated on 27/Sep/20
Ifα,β,γ,δarethesmallestpositiveanglesinascendingorderofmagnitudewhichhavetheirsinesequaltothepositivequantityk,thenthevalueof4sinα2+3sinβ2+2sinγ2+sinδ2isequalto
Answered by mr W last updated on 27/Sep/20
sinα=sinβ=sinγ=sinδ=k>0⇒α=sin−1kwith0<α<π2⇒β=π−α⇒γ=2π+α⇒δ=3π−α4sinα2+3sinβ2+2sinγ2+sinδ2=4sinα2+3sin(π2−α2)+2sin(π+α2)+sin(3π2−α2)=4sinα2+3cos(α2)−2sin(α2)−cos(α2)=2(sinα2+cosα2)=2(sinα2+cosα2)2=21+sinα=21+k
Commented by ZiYangLee last updated on 29/Sep/20
thankyousir...
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