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Trignometry

Hot goIITian

Joined:	4 Jun 2012
Post:	138

19 Jun 2012 21:38:32 IST

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280

plz solve this trigonometry

Engineering Entrance , JEE Main , JEE Advanced , Mathematics , Trigonometry

if then

a)125

b)250

c)50

d)75

Comments (3)

harshika rai

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Joined: 4 Jun 2012

Posts: 138

21 Jun 2012 19:02:25 IST

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plz solve it if any one knows.Its urgent.by the way the answer is 250.

rajat sharma

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Joined: 26 May 2010

Posts: 1362

21 Jun 2012 19:13:08 IST

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in LHS...write sin four x as sin square x ka whole square and similiarly for cos four x write cos square x ka whole square....now whose the most important formula of trigo-----sin square x is equal to 1 - cos 2x divided by 2 and cos square x is equal to 1 + cos 2x divided by 2 and then simplify ..it becomes a quadratic in cos2x which is a perfect square from which u obtain ...cos square x and from this sin square x ...and hence u know cosec 6 x and sec 6 x ...and the answer comes to be 125 + 125=250!!!

harshika rai

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Joined: 4 Jun 2012

Posts: 138

22 Jun 2012 15:35:47 IST

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thank you very much

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