Buktikan identitas identitas berikut 5sos²a - 4= -5sin² + 1

[tex]\cos^{2}{a}+\sin^{2}{a} = 1[/tex]
maka
[tex]\cos^{2}{a}= 1-\sin^{2}{a} [/tex]

[tex]5\cos^{2}{a}-4= 5(1-\sin^{2}{a})-4 = 5 -5\sin^{2}{a}-4[/tex]
[tex]= -5\sin^{2}{a} + 5-4 = -5\sin^{2}{a} + 1[/tex]
terbukti!
[tex]5\cos^{2}{a}-4= -5\sin^{2}{a} + 1[/tex]