Posted by Kristien on Saturday, February 23, 2013 at 7:43pm.
Sin4A  cos4A = sin2A  cos2A
Can i just square root the left side??:O

Trig identities:(  bobpursley, Saturday, February 23, 2013 at 7:52pm
I don't think it is an identity.
let A=90 deg
sin(360)cos(360)=01
sin(180)cos(180)=0+1
The sides are not equal.

Trig identities:(  Kristien, Saturday, February 23, 2013 at 8:17pm
?? Im sorry i don't understand what u did but im sure that this is an identity we have to prove that the left side equals the right side:)
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