IIT JEE , AIEEE Forum - Mathematics , Trignometry

m.viddya

Q.x=sin³20 - 3/4 sin 20 and y=cos³10 -3/4 cos 10 then?

1.x+y=0

2.x-y=0

3.x+y=1

4.x+y=2

raulrag009

x+y=0

$\frac{4\sin^{3}{20}-3\sin{20}}{4}+\frac{\cos^{3}{20}-3\cos{20}}{4}=x+y\\\\ \frac{-\sin{60}}{4}+\frac{\cos{30}}{4}=x+y\\\\ -\frac{sqrt{3}}{4}+\frac{\sqrt{3}}{4=x+y}\\\\ x+y=0$

uday_zingtudor

4x = -sin3(20)

4y = cos3(10)

x=-rt3/8 and y =rt3/8

x+y = 0

~Cheerio!!!

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