- #1
Born2Perform
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[tex]cos(2x)=2cos^2(x)-1[/tex]
what algebrical rule guarantees me thet is right to divide both angles for 2:
[tex]cos(x)=2cos^2(x/2)-1[/tex]
what algebrical rule guarantees me thet is right to divide both angles for 2:
[tex]cos(x)=2cos^2(x/2)-1[/tex]