Answers

2014-11-04T17:29:24+05:30
Ans of que .2)

we know
sin(90-Ф)=cosФ
so...
sin20=cos70
so,
=sin20×cos70+cos20×sin70
=sin²20+cos²20
by pythagoras identity,
sin²+cos²=1
so
sin20×cos70+cos20×sin70=1
ans of que 1)
=(cos
²20+cos²60)/(sin²40+sin²50)
we know
sin(90-Ф)=cosФ
so
=(cos²70+sin²70)(sin²50+cos²50)
by pythagoras identity,
sin²+cos²=1
so
=1/1
=1







1 5 1
The answer for Q1 isn't right
thn
Can you type the question again in comments?
ya
cossqare20+cossqare65 whole divided by sinsqare40+sinsquare50
The Brainliest Answer!
2014-11-04T17:33:51+05:30

 \frac{cos^220+cos^265}{sin^240+sin^250}= \frac{cos^220+cos^265}{sin^240+cos^240}= \frac{cos^220+cos^265}{1}

 \frac{cos^220+cos^265}{1}=  \frac{1.0616284167162193544398746203241}{1}
used a calculator
as sin^2x+cos^2x=1,sin(90-x)=cos(x)
given x lies in first quadrant
sin20(cos70)+sin70(cos(20))=
=(sin20)*(sin(90-70))+cos(20)(cos(90-70))=
sin^220+cos^220=1
2 5 2
it is correct only
according to the question given
but i didnot report
ok
it is not right to use calculator.. u need to simply in Sine, cos rations