InterviewSolution
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Evaluate the following limit :\(\lim\limits_{\text x \to0}\left\{\cfrac{3\text x^2+1}{4\text x^2-1}\right\}^{\cfrac{\text x^3}{1+\text x}}\)lim(x→∞) {(3x2 + 1)/(4x2 - 1)}x3/(1 +x) |
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Answer» As we need to find\(\lim\limits_{\text x \to0}\left\{\cfrac{3\text x^2+1}{4\text x^2-1}\right\}^{\cfrac{\text x^3}{1+\text x}} \) lim(x→∞) {(3x2 + 1)/(4x2 - 1)}x3/(1 +x) We can directly find the limiting value of a function by putting the value of the variable at which the limiting value is asked if it does not take any indeterminate form (0/0 or ∞/∞ or ∞-∞,1∞ .. etc.) As it is taking indeterminate form- ∴ we need to take steps to remove this form so that we can get a finite value. Z =\(\lim\limits_{\text x \to0}\left\{\cfrac{3\text x^2+1}{4\text x^2-1}\right\}^{\cfrac{\text x^3}{1+\text x}} \) Take the log to bring the term in the product so that we can solve it more easily. aking log both sides- {using algebra of limits} Still, if we put x = ∞ we get an indeterminate form, Take highest power of x common and try to bring x in denominator of a term so that if we put x = ∞ term reduces to 0. {∵ log (3/4) is a negative value as 3/4 < 1} \(\therefore\)LogeZ = \(\Rightarrow\)Z = e-∞= 0 Hence, \(\lim\limits_{\text x \to0}\left\{\cfrac{3\text x^2+1}{4\text x^2-1}\right\}^{\cfrac{\text x^3}{1+\text x}} \)= 0 |
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