Cos²20+cos²65whole by sin²40+sin²50 find the value


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this question is wrong .........we cant simplify Cos²20+cos²65....for more detailes see same question posted on yesterday....also see its comments....delte this question
it is not cos20 25
means
it's not cos square 20 it is cos square 25

Answers

2014-11-05T19:29:33+05:30
Bye using some corrections given in comments,
sin(90-Ф)=cosФ
and  by pythagoras identity,
sin²+cos²=1
so.....
=sin²25+cos²25/(sin²50+cos²50)
=1/1
=1
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