Jawab:
Nilai Lim cos 2x
x ➝ π/4 cosx – sinx
= Lim cos²x – sin²x
x ➝ π/4 cos x – sin x
= Lim (cosx + sinx)(cosx – sinx)
x ➝ π/4 (cosx – sinx)
= cos π/4 + sin π/4
= cos π/4 + sin π/4
= 1/2 √2 + 1/2 √2
= √2