Prove this identify :
2 cos^2 (45°-A ) = 1 +sin 2 A ​

I am guessing that you mean 2cos2(45° - A) = 1 + sin2A

According to a double angle identity, 2cos2θ - 1 = cos(2θ)

So, 2cos2(45° - A) - 1

= cos (90° - 2A) =cos90°cos2A + sin90°sin2A = (0)cos2A + (1)sin2A = sin2

Thus, 2cos2(45° -A ) = 1 + sin2A

a variable is any characteristics, number, or quantity that can be measured or counted. a variable may also be called a data item. hope i !

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

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