Posted by Kristien on .
Sin4A  cos4A = sin2A  cos2A
Can i just square root the left side??:O

Trig identities:( 
bobpursley,
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,
?? 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:)