Limit cos 2x/cos x-sin x dimana x mendekati x/4

LimiT

lim x→π/4 cos 2x / (cos x – sin x)

= lim x→π/4 (cos x + sin x)(cos x – sin x) / (cos x – sin x)

= cos π/4 + sin π/4

= 1/2 √2 + 1/2 √2

= √2