Show sin^2 x cos^2 x = (1 – cos(4x)) / 8 by filling in the table below. Start with the left hand side.

Question

anonymous · Answer

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anonymous · Answer

@RadEn this is the last proof for today, i promise :)

raden · Answer

sin^2 x = (1-cos(2x))/2 and
cos^2 x = (1+cos(2x))/2
reason = those are identities

the simplify form would be 1/4 (1 - cos^2 (2x))

cos^2 (2x) = (1 + cos(4x))/2 
reason = an identity like the first reason

1/4 (1 - cos^2 (2x)) = 1/4 ( 1 - (1 + cos(4x))/2 ) = 1/8(1 - cos(4x))
reason = just simplifying form the 2nd reason  

maybe :)

anonymous · Answer

haha thanks, but what is the maybe about?

raden · Answer

maybe my reason is right, or it can be wrong too :) this link might useful : http://2000clicks.com/mathhelp/GeometryTrigEquivIdentities00.aspx

anonymous · Answer

Ok ok, but do you think it is right? Like it does make sense haha so I don't see why it would be completely wrong

raden · Answer

i hope my reason is right :)

anonymous · Answer

what identities are used in the reasons?

anonymous · Answer

@RadEn