sin a.cos a/cos^2a-sin^2a=tan a/1-tan^2a mohon dijawab ya pake cara lengkap

[tex]\frac{sin(a)cos(a)}{cos^2(a)-sin^2(a)}=\frac{tan(a)}{1-tan^2(a)}[/tex]
[tex]\frac{sin(a)cos(a)}{cos(2a)}=\frac{tan(2a)}{2}[/tex]
[tex]2sin(a)cos(a)=sin(2a)[/tex]