tunjukan bahwa cos² 45° +sin² 45° =1

cos² 45° + sin² 45° = 1
(½√2)² + (½√2)² = 1
(¼ × 2) + (¼ × 2) = 1
2/4 + 2/4 = 1
4/4 = 1
1 = 1 (terbukti)

cos ama sin 45 kan setenfah akar dua jadi :
[tex] (\frac{1}{2} \sqrt{2} )^{2} + (\frac{1}{2} \sqrt{2} )^{2} \\ = \frac{1}{4} x2 + \frac{1}{4} x2 \\ = \frac{1}{2} + \frac{1}{2} = 1[/tex]