SOLUTION: 1-(cosB-sinB)^2=sin2B

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Question 232731: 1-(cosB-sinB)^2=sin2B
Answer by chibisan(131) About Me  (Show Source):
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1-(cosB-sinB)^2=sin2B

L.H.S
1-(cos^2B-2sinBcosB + sin^2B)
1-cos^2B + 2sinBcosB -sin ^2B

by using sinB+cosB=1
and 2sinBcosB=sin2B (double angle)

sinB + sin2B - sin^2B
= sin2B (proven)