2.8-bo'lim : Infinity chegaralari, II qism
9. \(\displaystyle \mathop {\lim }\limits_{x \to \,\infty } \ln \left( {\frac{{11 + 8x}}{{{x^3} + 7x}}} \right)\) ni baholang.
Yechim
Avval e'tibor bering,
\[\mathop {\lim }\limits_{x \to \,\infty } \frac{{11 + 8x}}{{{x^3} + 7x}} = 0\]Agar siz ushbu cheklovga ishonchingiz komil bo'lmasa, avvalgi bo'limga qaytib, ushbu turdagi limitlarni amalga oshirishingiz mumkinligiga ishonch hosil qilish uchun u erdagi ba'zi misollar bilan ishlashingiz kerak.
Shuni ham yodda tutingki, biz \(x \to \infty \) chegarasini baholayotganimiz sababli, \(x > 0\) deb taxmin qilish xavfsiz va shuning uchun yana shuni aytishimiz mumkin:
\[\frac{{11 + 8x}}{{{x^3} + 7x}} \to {0^ + }\]Endi eslash 5-misol Ushbu bo'limdan biz bilamizki, argument chegarada o'ngdan nolga o'tganligi sababli javob,
\[\mathop {\lim }\limits_{x \to \,\infty } \ln \left( {\frac{{11 + 8x}}{{{x^3} + 7x}}} \right) = \require{bbox} \bbox[2pt,border:1px solid black]{{ - \infty }}\]